Looking for Indoor Activities for a 21 Month Old

Shameless plug here, but how about traveling over to Woonsocket, RI to visit Stuffing Station? :) We are a make-your-own-stuffed-animal retailer where kids hand stuff their own animal (various sizes starting at $8.99.) We also have tables where kids can color, a big chalkboard on the wall for playing, etc. Kids have lots of fun there!
Other ideas... McDonald's play lands, Belmont playspace,Westford Family Fun and Fitness Center (they have an indoor playground), playspace in Woborn, etc. Or if these things are too far for you to travel, how about joining a local mom's club and rotating homes for playgroups?

Try Perpetual Motion in Lowell. I have a 4 yr. old, a 21 month old and a 6 week old. We all love going there and it is reasonably price!!!!!!!!!!

I love Gymboree in Auburn. I have 3 boys and have brought them all to classes in the winter months. They can climb, jump and sing songs. I also used Whitinsville Community Center www.ourgym.org. I have never been but I think Oxford started a community center. Oxford also has a nice Library.

Hi - there is "playtown express" in hopkinton and "pump me up" on rt9 in Shrewsbury. Also the YMCA in worcester (greendale branch) is supposed to be great for toddlers. I've also heard the Library in Oxford is good too.