Immediately, if you can.  Seriously, this is one of the most charming films I’ve seen in ages. If you were a theater geek or an art geek (like me) in High School, you will love it.  I think you’d probably love it regardless, but there’s some extra special nostalgia for those of us that were on the quirkier side.  Oh & have some extra mascara handy for when  you do . . .