I saw a short little article in US Weekly yesterday about this guy who was starring in a video or something with Britney Spears - anyway, it was about her losing her virginity to him in the video and the guy said that since she was doing a striptease in bra and panties two inches from his nose, he was debating whether or not to wear two jockstraps, but decided one tight one was sufficient.
So I'd say yes, they do occasionally get woodies.