The event, now in its sixth year, commences at a meet-and-greet with the cast and creative team April 6, prior to the performance April 7. 

The musicals will be written, cast, rehearsed and performed over the course of a single day. Each person will bring a prop and a costume to the meet-and-greet to inspire the writers, and the actors and directors leave at 11 PM, when the composers and book writers begin writing. 

Completed musicals, featuring at least two songs, are due by 7 AM. In the morning, directors, choreographers and actors arrive for rehearsals. A technical rehearsal is held in the late afternoon, and the audience arrives in the evening, when the musicals are performed without scripts in hand.

"Every year, a wonderfully talented group of the best from stage and screen come together to attempt the impossible," Ari Edelson, artistic director of the Exchange and the Orchard Project, said in a statement. "This combustive and joyous process is not only hugely entertaining, but it also raises the funds to support the beginning of dozens of shows that then go up around the country. It would not be a stretch to say that All The Way, which just opened on Broadway, would not be the great piece that it is without the the support of this event, as the play was written over two summers at the Orchard Project."

Past participants have included Ben Folds (Ben Folds Five), America Ferrera ("Ugly Betty"), Mo Rocca (The 25th Annual Putnam County Spelling Bee), Debby Boone (Grease, Seven Brides for Seven Brothers), Cheyenne Jackson ("30 Rock"), Rachel Dratch ("Saturday Night Live"), Jesse Tyler Ferguson ("Modern Family"), Anthony Rapp (Rent, If/Then), Kathleen Turner (Cat on a Hot Tin Roof, Who's Afraid of Virginia Woolf?), Roger Bart ("Desperate Housewives," The Producers), Richard Kind (The Big Knife, "Mad About You"), Steven Pasquale (The Bridges Of Madison County, Far From Heaven), Taran Killam ("Saturday Night Live"), Tracie Thoms ("Rent," "Cold Case") and Tonya Pinkins (Caroline, or Change). The event benefits the Exchange’s summer retreat, The Orchard Project, which kick-starts innovative new theatrical work from around the world.

Visit exchangenyc.org/201424HM for more information.