Don’t be fooled into thinking these performers have good intentions when they ask for your favorite holiday memories. Uncle Mike Ruins Christmas (Saturdays through December 27) is an hour of improvisational acts based on your cherished family moments. That is, until the dreadful beer-guzzling Uncle Mike (Mike Murphy) barges in and shits all over those memories. During one recent show, someone’s fond recollection of discovering a family of squirrels in their home on Christmas Eve (groan) became a war between a knife-wielding Uncle Mike and his vegan sister-in-law (yes!). The cast then trampled all over a woman’s childhood memory of waking up to find evidence of Santa’s visit. Murphy and his cohorts from Jet City Improv skillfully transform seasonal fodder into a hilarious and perverted ruckus each week. And while some improvisations don’t work as well as others, there’s the general satisfaction of watching groan-inducing Hallmark sentiments churned into late-night ribaldry. If only our actual family gatherings were that much fun. Historic University Theater, 5510 University Way N.E., 800-838-3006, www.jetcityimprov.com. $8. Sat. at midnight:30 (i.e. Sun. morning). Ends Dec. 27. ERIKA HOBART

Saturdays. Starts: Nov. 22. Continues through Dec. 27, 2008