J.S.
I haven't done gymboree but I am doing My Gym and my son loves it. They work on building the core strengths of the body, helping with large and fine motor skills, plus social. You get a free class with My Gym so you can try it out before seeing if you like it or not.
I second the other mom's advice in washing hands... I also take Wet Ones antibacterial hand wipes... I'll never understand why parents take their sick kids to places, but they do.