An odd double bill by two companies, "Flipside" has a snappy second half. Taco Flavored Eggrolls' Eat This! A Culture-Ostomy begins with unabashedly enthusiastic dancing to Billy Idol and maintains the high-energy hilarity throughout its 55 minutes of sketch comedy. Exploring ethnicity in fresh and funny ways, the company mainly depicts clashing cultures, often across generations. A director might have helped tighten the performances and rein in a sprawling staging, but for the most part this is a quick-witted, fast-paced show rich in original material. It's vastly different from Common Man's Doubleplay, 30 minutes of dramatic improvisation by Joe Yau and Ranjit Souri. Given Pinter-worthy pauses by director Jonathan Pitts, it's interesting but more an actors' exercise than a treat for the audience. Through 1/19: Thu 8 PM, no show 12/22, Athenaeum Theatre, third-floor studio theater, 2936 N. Southport, 312-902-1500 $12-$15.