It had to happen sometime: Tiff and Mom, Corn Productions' beloved dysfunctional mother-daughter duo, have finally tackled the roles they--or at least their creators, Robert Bouwman and Todd Schaner--were born to play. The two trade their usual characteristics: good-girl Tiff plays sociopath Rhoda Penmark and drunken slut Mom plays long-suffering matron Christine Penmark (well, she's still drunk and slutty, but in a Desperate Housewives kind of way). This parody of the 1956 film tends toward the obvious, and the music, by Scott Lamberty with lyrics by Bouwman and Schaner, begins to sound the same after a while (except for a brilliant Devo-inspired number). But the cast features some great supporting turns, particularly David Cerda as tightly wound school matron Miss Fern and Jeff Dean as the grieving, "piss-drunk" Mrs. Daigle. I laughed really hard through most of the show. Through 6/10: Wed-Fri 8 PM. Cornservatory, 4210 N. Lincoln, 312-409-6435. $6-$12.