Naples has some awesome botanical gardens that we attempted to go and see with a nifty coupon we received. Turned out not so much of a deal so we walked around outside and the kids had a great time anyway. Someday...
For playgroup here in florida we switch off going to different pools. My kids love it because we can not use the pool at the school. It is a fun alternative to the beach and a little cleaner.
We also enjoy going to the splash park right by our house, especially when its hot!