So do I! You're right near the Plainville store. We have a D&D Encounters game every Wednesday night at 7:00. It's a 4th edition game, one encounter per week, usually running until 9:00 or 9:30. The new edition is fairly different from 3.5 in terms of the mechanics, but in terms of rolling dice and being an adventurer, the basics are the same. Feel free to drop in and watch, or join! There are pre-generated characters, so no 4e rules knowledge is needed. If you want to make a character of your own, or just to chat about D&D a while, feel free to drop by early. I'm pretty much there all day.
I don't know of any other campaigns running at the store, but Wednesday evenings are probably a good time to see if anyone wants to get together and start one. I'm planning to do a 4e game based on Lord of the Rings at some point, but that's still in the early planning stages. If anyone out there wants to get a game going, chime in! We could use another DM around here.