Sometimes your friends invite you to things like an improv comedy show. Then you go, realize that you're not laughing, and try to decide what the best time would be to punch that same friend in the mouth. But there is good improv out there, and one of the best deals in town is at the Upright Citizens Brigade Theatre, where you can see two genuinely funny half-hour shows, back-to-back, for a mere $5. Every Thursday night at 11 p.m., Last Day of School and Convoy are performed by some of the top comedians UCB has to offer, and their weekly shows routinely play to packed, cackling houses (you can, and should, reserve your tickets online in advance). In Last Day of School, which has a popular "text message show" with scenes based on audience cell-phone in-boxes, the blond duo of Neil Campbell and Heather Campbell (oddly, no relation) particularly stand out. Bringing alcohol, according to the sign on the wall, is prohibited, but if that rule ever gets enforced, it would be a first. 5919 Franklin Ave., L.A. (323) 908-8702, ucbtheatre.com.