Started by a French artist named JR in 2011, Inside Out is a participatory art project that's going on all over the world. JR and his collaborators turn portraits into big posters and have the subjects plaster them up in public. It's a way for communities to make a collective statement, and take back the walls and buildings of their neighborhood from advertisers.

Usually people need to gather a group and send in digital photos to be transformed into posters in Inside Out's Soho studio, and then paste up the portraits themselves. However, through Friday, March 10, Inside Out is sponsoring a photo booth truck in Times Square where people can get their oversize pictures taken, and then watch as a team pastes them to the sidewalk.

Participating in the project is 100% FREE. All you need to do is sign a photo release and wait in line. Due to the location, they're getting a lot of tourists. But they're really hoping more natives come out and help take back Times Square from the big brands (at least until the next rainfall washes these posters away).

The Inside Out Project is definitely a cool thing to do with kids—I saw many families waiting on line to go when I visited yesterday. However, there are some important things to keep in mind to make your experience as fun and stress-free as possible.

Things to Know Before You Go

Know when (and where) to go The photo booth is stationed in Times Square (usually around 46th Street and Broadway, though it moves around from day to day) and will be open Friday, May 2 and Sunday, May 5 through Friday, May 10 from noon to 8pm. (It's closed Friday, May 3 and Saturday, May 4.) If you don't want to wait on a long line, arrive promptly at noon or even a little beforehand! Once afternoon comes, the wait time exceeds an hour.

Got a group of five or more? Then you can make an advance reservation Reservations for groups are accepted on Sunday, May 5 or Wednesday, May 8 from noon to 4pm. Email nyc@insideoutproject.net at least 24 hours in advance. There is one caveat: Your posters won't be plastered in Times Square. Instead, you'll be encouraged to take them back to your community and post them on your school or the side of your building, anywhere that's publicly visible. It takes some doing—you'll need to watch a YouTube video about how to wheat paste and get some kind of approval—but it's definitely a fun project for kids, who get a real kick out of seeing their oversize faces plastered on a wall.

Strike a pose Funny, silly, stoic, ecstatic—pretty much anything goes with these portraits. Some people use props. Others just sit and stare. You can see all of the NYC photo booth pics online to get a sense of how diverse they are.

Love the pic so much you wish you could keep it? Inside Out emails you a digital image. You even get your very own URL that you can forward to friends so they can download it, too.

Rather watch than participate? Just come down to Times Square to see the art project in action. It's pretty cool to watch the truck spit out these massive pics and to literally walk across hundreds of people's faces.

Live in an outer borough? Before the photo booth parked in Times Square, it traveled to Sandy-ravaged areas of Staten Island, Red Hook, the South Bronx and Rockaway, and snapped portraits of the residents. Many of those posters are still up in those neighborhoods.

Want to learn more? The new documentary Inside Out, The People's Art Project screens on HBO in May.