It's every leftover Beavis and Butt-head fan's dream: the former stars of Mystery Science Theater 3000, now with RiffTrax.com and Weird Al Yankovic, all together for a screening of holiday shorts. RiffTrax: Christmas Shorts-Stravaganza! is a live broadcast of the snarky foursome's comical commentary on seasonal flicks, including a musical short praising pork and a bizarre Rudolph the Red-Nosed Reindeer. As a bonus, audiences will get insider info - a Web site address and code that allows fans to download shorts, photos and music (okay, it's a holiday song by the RiffTones - Michael J. Nelson, Kevin Murphy, a.k.a. Tom Servo, and Bill Corbett, a.k.a. Crow T. Robot - so we're not sure exactly how musical it is, but hey, it's free). A filmed repeat of Wednesday's screening is set for Thursday. 7 p.m. Wednesday and Thursday. Various theaters, including Edwards Houston Marq*E 23 & IMAX, 7620 Katy Freeway. For information, visit www.rifftrax.com. $12.50.