Didja' do the half-mumbling explanation about Rifftrax and why you were actually buying the DVD... only to get a sad look from the clerk, like "Sure, sure... you poor, pathetic little man"?
Thankfully, there are a few clerks at the video store on my way to work that know the drill by now. Last time i went in, they actually asked if i was "the Rifftrax guy"! I'm not sure if that was meant to be like, a compliment... or something more like a Bigfoot-sighting. But, at least i don't have to explain why i'm renting Battlefield Earth and Troll 2 anymore!