Robin Williams was in top form at Bob Woodruff’s Stand Up for Heroes event at the Beacon Theatre on Thursday, poking fun at sexting politicians, including Anthony Weiner. Returning to stand-up after a long break, he joked about a new app, “It’s for politicians. It’s called a Cockus Blocker. You take a picture and it immediately pixillates your penis, puts it into a kind of Rubik’s Cube witness- protection program.” Williams told us before the show to benefit the Wounded Warriors Project, “I really just started again so I haven’t gotten enough to go out and do a full stand-up set. I’ve got about 20 minutes [of stand-up] that’s maybe usable. It’s the thing Louis [C.K.] told me, and Chris Rock said, you just go out and do it . . . hope for the best.” Others who took to the stage included Jon Stewart, Ricky Gervais — who amazingly reused some of the same jokes he did at last year’s event — and Mike Birbiglia. Patton Oswalt also performed, as well as John Mayer, Roger Waters backed by a group of soldiers, and Bruce Springsteen.