"Here's a clue--don't mess around, you won't get STD's."
Another thing I forgot to mention: herpes has been shown to survive in a hot tub environment, and there's been at least one documented case of a girl with eczema who contracted one of the benign strains from sharing a hot tub with someone who had fever blisters at the time. That's why I never go in hot tubs.
There was also a case a few weeks back about high school wrestlers (five, I believe) who said they got it from the wrestling mat. That's their story and they're sticking to it.