This was the description from a photograph site that JW posted in the pictures thread:
"Andy Roddick is the latest celebrity to fall victim to prankster Ashton Kutcher as he gets Punk'd in Hollywood, Ca as part of the hit MTV series. The Tennis player who used to date singer Mandy Moore was the passenger in a limo that was traveling along a winding Hollywood road when they encountered a roadblock and where unable to pass when Andy's limo driver who was in on the gag attempted to drive past the roadblock the car got a severe drenching of water from a nearby truck."
If it's the road in Hollywood I think it is, it's this nasty windy twisty turny road through the Hollywood Hills - it's really a bitch to drive let me tell you. And it's been closed lately due to the horrendous rain, so it makes sense with water and stuff like that. Not the best Punk they've ever done (That's either the Beyonce Christmas massacre or when they wouldn't let Halle Berry into her own premiere
), but it should be funny nonetheless.