Seconding the mom's Facebook groups. They've been super helpful to me to find/recommend activities in the area. As far as mommy and me classes, we've done swimming through classes like British Swim School/Goldfish, but I've seen gymnastics/music classes as well. You might also have luck with library story times, but they can be hard to participate in if you happen to have a 9-5 schedule. My kids have loved them though when we could go.