Earlier this week, several authors of young adult fiction met up at GalleryBar on the Lower East Side for a party celebrating the publication of 21 Proms, a new anthology of prom-themed stories. Like the book itself, the party was a benefit for Advocates for Youth, a non-profit organization that provides educational resources on sexual health and reproduction issues for teens. Among the many writers in attendance were (in the front row) Aimee Friedman, Sarah Mlynowski, Libba Bray, co-editor Dan Ehrenhaft, and Emily Jenkins, then (in the back) Lisa Sandell, Leslie Margolis, co-editor David Levithan, and John Green. (Also, we hear, Emily Gould was there, too.)