For the past nine years, the Upright Citizens Brigade Theatre has been not only a great place to catch members of the original improv troupe, but also a venue where you can see some of the city's rising alt-comedy performers before they hit it big. While alums like Human Giant and the Whitest Kids U'Know may attract sellout crowds now, they earned their stripes at the theater's gut-busting showcases. This year's summer roundup may be your last chance to check out John Gemberling or Kate McKinnon without a two-drink minimum.