H.L.
There's a mom's group in Boca at the Spanish River Church on Yamato; we/they meet on Wednesdays at 10:00-noon. The group is open to all denominations or nondenominations, if you will. There is one group for babies 0-3 months and then 4 months on.
A lot of mommies to meet!
There are a number of exercise groups including a Mom and Me type at Sugarsand Park in Boca; they meet on Tu/Th at 10:30 I believe. Gymboree in Boca has a mommy/me Yoga and Babies R Us in Boca has a stroller group that meets next Thursday at noon I believe.
Good Luck!