It's got about a 2 week incubation period. Once you break out in the rash, you're no longer contagious. My 10 year old son had it first, and it didn't slow him down at all. My 7 year old daughter got it exactly 2 weeks later, and she had a week or so of joint pain (which is common). Neither of my kids ran a fever, but many kids do. It's really no big deal, but it can, in rare instances, cause problems for the fetuses of pregnant women (most adults are already immune to it, though).