I used to register for my daughters for classes here at Daley Bicentennial Plaza, they have great Moms and Pops class, I knew lots of people from the classes and my kids got to know lots of friends. If you are a new mom, this is a perfect place for you to go to hang out.
The fees are pretty cheap, $50 for a whole term, normally around 2-3 months. Here is the information for this summer program.
SUMMER 2009 PROGRAM SESSION DATES
Program information available for viewing online: Monday, April 6
Online registration begins: Monday, April 20 at 9am
In-person registration at most parks* begins: Saturday, April 25
Online registration ends: Sunday, June 14
General program session runs the weeks of: Monday, June 15 – Sunday, August 23
Camp session (for most camps) runs June 22 – July 31
Moms and Pops is great, I went there several times. The kids can learn how to interact with other kids and share (or fight).