worcester area?

does anyone know of any active things to do with a toddler? id really like to stay active and not just on my wii fit (although it is kicking my butt!) but saturdays are my day alone with my son (husband works) and i didnt know if anyone had any suggestions of things i can do to keep myself active and my son too that we would both enjoy. i was planning on taking him to the park tomorrow but the rain probably made it all muddy. lame!

the Roger Williams Zoo has nice walking/stroller paths, and a park area all around it, with a nice
playground for toddlers (near the carousel). 

The ecotarium is always a fun choice. So much to see. Both indoors and out. Very kid friendly.

Hope this helps.