my BF works in electronics retail. He had a customer ask him once what website he could go to so he could download more memory for his computer.
He also had a customer come in asking for a "large car charger" for their cell phone. Apparantly he had an LG phone, and thought that the "LG" meant "large"
Yahoo!Answers has a lot of them.. there are youtube videos dedicated to stupid q&a on there.
Funniest one I saw was someone asking if it would be cheaper to get their dog spayed or neutered. They wanted to get their dog fixed, but wasnt sure which procedure would be cheaper to ask for.