The day the governor of Rhode Island announced that schools would remain closed for the rest of the school year, Dan Freedman rallied his high school classmates to gather for an impromptu car parade on campus.

Their prom and graduation may not happen, but the Cumberland High School class of 2020 would have its honk out anyway. And if it had to happen on April 23, and not in June, so be it.

“When school got canceled, we were angry and confused and venting,” said Dan, 17, who lives in Cumberland, R.I., with his parents and younger sister. “It just felt like we needed to do something.”

About 75 cars assembled on the sunny spring afternoon, carrying roughly 100 seniors. When all the cars were in place, Dan gave the signal to his classmates to start and took off in his green Toyota Highlander.

Like millions of other students around the country, the seniors of Cumberland High School were mourning the loss of a season of celebration, and eager to eke out a little togetherness, despite the mandatory separation.

School and university buildings may be shut, but about 3.7 million high school students and almost four million college and graduate students are still expected to get degrees this year, according to the National Center for Education Statistics, and many are looking for ways to commemorate the occasion during a bleak time.

School administrators around the country have been delaying ceremonies, holding them in unconventional locations like drive-in cinemas, or hosting virtual ones online. Car parades, door decorations and impromptu visits from the principal have replaced commencement speeches and graduation parties.

As families cancel restaurant, hotel and plane reservations, they’ve been left scrambling to salvage what they can of a marooned milestone.

“These are really huge losses for kids,” said Dr. Helen Egger, the chairwoman of the department of child and adolescent psychiatry at NYU Langone Health. Missing out on the events of the season “is exacerbated by the fact that you can’t be with your friends.”

Celebrities have been stepping in to fill the void, with star-studded events happening this weekend online and on television. On Friday, Oprah Winfrey will give a commencement speech on Facebook, geared not to a single institution, but to those graduating from many different high schools and colleges across the United States. The event will also include other stars, including Awkwafina, Jennifer Garner and Lil Nas X.

And on Saturday, former President Barack Obama will speak at two virtual events, including one organized by LeBron James’s foundation that will also feature athletes, musicians and others, including Megan Rapinoe, Pharrell Williams and Malala Yousafzai, airing on ABC, CBS, FOX and NBC and on social media.

But a televised special hardly replaces the real thing, and a virtual commencement runs the risk of feeling like a flop, as a “Saturday Night Live” cold open made abundantly clear last weekend. So to salvage the moment, some families are getting creative, turning living rooms, front lawns and residential streets into alternate sites.

Dan’s parents, Karen and Jason Freedman, had to cancel a backyard graduation party with 150 guests. Instead, they’re turning their front porch into a homage to their son, decorating it in a barbershop theme as part of a school decoration contest. They bought a light-up barber pole and a six-foot-long banner, a nod to a student fan group their son created with a friend.

Ms. Freedman hopes that in the summer they may be able to have a small backyard party with a few of her son’s friends, holding a mini at-home ceremony. But even that may not be possible. “While I’m an optimistic person naturally, this has been difficult,” she said.

Other schools and families are bringing the pomp and circumstance into their living rooms. Requests for boxed party supplies have quadrupled at Little Miss Party Planner, a Manhattan event planning business, since the country shut down. The $69 All Out Grad box includes place settings, balloons, sparklers, a graduation cap and a “words of wisdom” PDF card for friends and family to fill out.

“I can’t even keep up with the demand,” said Seri Kertzner, the owner of Little Miss Party Planner.

In the past week, sales of graduation cards have surged on Minted, an online marketplace. “Now people understand we’re not having graduations,” said Mariam Naficy, the founder and chief executive of Minted. So the question becomes, she said: “How do I celebrate my grad?”

Minted released new cards, with language that reflects the somber mood, like ones that say, “Stronger for This,” or “So This Guy Just Graduated. Virtually.” Some graduates have put photos of themselves in masks on their cards. Ms. Naficy recommends framing such portraits. “It’s kind of like graduating in the middle of a war,” she said. “Maybe one way to make peace with it is to treat it as the historical moment that it is.”

When Angela Carlyle learned about a month ago that the graduation ceremony for the Evergreen State College Tacoma campus in Washington would be canceled, she knew, as a member of the school committee that plans the graduation, she had to do something for her classmates.

“I was really sad and really, really thinking about my whole community at school,” said Ms. Carlyle, 38, an art and advocacy major.

At Evergreen Tacoma, the average student age is 38, and many students are parents. So graduation is a community event, with dancing, food and a parade through the neighborhood. “Graduation means so much,” said Marcia Tate Arunga, the dean of the school. “How do we celebrate this life change, not for this one person, but for the entire community?”

Ms. Carlyle contacted Confete Party, a local party supply company, to see if it could make custom boxes for the roughly 70 graduates, with balloons in the school colors, confetti, cookies, plastic champagne flutes a journal and a school tassel.

The company hadn’t assembled such an order before, but saw an opportunity to replicate it, and now sells virtual boxes online for $30, so guests in different locations can share in the same party theme.

Next month, Evergreen students will collect their boxes from the school, a bouquet of flowers and a meal, a choice of three dishes prepared by local restaurants: barbecue beef, chicken or a vegan and gluten-free option. And of course, graduates will also be photographed accepting their diplomas. The school will create a video of the graduates, livestreaming it on June 13. Ms. Carlyle plans to wear her cap and gown at home that day with her husband and two children, as her classmates celebrate in their homes with the same food and decorations.

“I’m trying to see this as an opportunity for me to share this day with more people,” Ms. Carlyle said, since friends and family who would not have traveled to Washington for the ceremony will be able tune into the virtual event instead.

Some homebound celebrations have been surprisingly cathartic. Claire McHugh, 22, was disappointed that there would be no ceremony to honor the end of her college years at Northeastern University, where she graduated summa cum laude with a bachelor’s of science degree in biology.

“It was heartbreaking. We had such plans. I had literally booked the hotel nine months in advance,” said Ms. McHugh’s mother, Yvonne Kruiten. “Right away, I knew that we couldn’t let the day pass without some sort of recognition.”

Ms. Kruiten considered inviting friends and family to drive by the family home in Montclair, N.J., but even that felt potentially risky. And could she really ask people to drive all that way just to wave?

So instead, she asked them to share video messages, which Ms. McHugh’s boyfriend compiled into a montage. Ms. Kruiten ordered decorations and a cap and gown online, hiding the boxes in the basement.

On May 1, she told her daughter to prepare for a celebration. “I told her we were all going to get dressed, so everyone needs to shower and look good,” Ms. Kruiten said.

Ms. Kruiten and her husband, Chris McHugh, were the M.C.’s, playing a 2011 commencement speech Amy Poehler gave at Harvard University. At one point, Ms. McHugh was told to leave the living room and wait for her parents to call her name so she could walk back in and accept her diploma. Speeches were made. Afterward, the family played cornhole and drank mimosas in the backyard.

“Throughout the course of the day, I ended up having that moment: I really am done with college,” Ms. McHugh said.

Even the smallest of ceremonies can have a big draw. On April 30, Trent B. Johnson Jr. celebrated his graduation from medical school at Ohio State University in his mother’s living room in Orlando, Fla. Only his parents, grandparents and siblings attended. About 40 friends and family tuned in over video to watch him cross his living room in a cap and gown.

But then his audience grew. Within hours of posting the video on Twitter, the tiny event went viral, eventually attracting 35,500 likes.

Mr. Johnson, 29, the first member of his family to graduate from medical school, saw the attention as a sign of hope, and all the notifications buzzing his phone as a parade of virtual cheers not just for him, but for the class of 2020.

“We are the class that’s going to show the rest of the world that we are resilient,” he said. “And we are going to walk no matter what.”