Mad props to anybody who can surf Tahoe. I don't think it's possible.
Don't go to wild island. It's over priced, unsanitary, and you spend more time waiting in line than the drive from Tahoe to Sparks.
Just hang out at the beach, and I'm sure you can find people to party with in south lake. Go hiking, or like previously said, go kayaking/swimming/jetskiing. Walk around Heavenly Plaza or take the gondola up to heavenly and check out where we ride. There's plenty to do. If I wasn't in Italy, I would definitely show you what's good in Tahoe!