Most people shudder when they hear the words "improv comedy" it's about as popular as a steak in Berkeley. Shaun Landry, the producer of the 2006 San Francisco Improv Festival, obviously doesn't care; she's determined to pull this series of shows off anyway. Last weekend ImprovBoston brought us ¡Ay Diego!, featuring Will Lurea and Zabeth Russell. The performers started off as Latin characters Juanita and Diego, then morphed into everything from a psychiatrist who prescribes a "pirate disguise" as a cure for shyness to a professional sock man who tells his customer, "Ma'am, I like you ... and I like your feet." In a few spots their rhythm was slightly off, but Lurea and Russell have an easy chemistry and a seemingly endless supply of funny material. Next on the bill was True Fiction Magazine, a group of five actors who construct noir comedy shows around titles called out by audience members. The rapport between these performers and the subtle keyboardist who accompanied them was impressive as they crafted a story out of the title "My Ass." This year the festival features improvisational talent from all over America: Keep your eyes peeled for Dad's Garage out of Atlanta; New York City's I Eat Pandas, an acclaimed trio that improvises entire musicals; and Los Angeles' The Group, under the guidance of veteran director David Razowsky. These acts give us the experience of watching the creation of something that's never happened before and will never happen again.