Hi M.,
Don't know that you necessarily would be worried, but I just wanted to say that I wouldn't worry about speech delay (suggested below)--a dozen words at this stage is terrific.
Also, kids who sign do talk a *tiny* bit later on average, but it's not really a meaningful difference (I think it's a month or so), and there's no lasting difference in the long-run.
My mother-in-law got me a few well-reviewed books on activities for toddlers. I haven't read any of them yet, so I can't speak to their usefulness from personal experience, but you might check them out if you're interested. Here are the titles:
1. Things To Do with Toddlers and Twos, by Karen Miller
2. 365 Games Toddlers Play: Creative Time to Imagine, Grow, and Learn, by Sheila Ellison
3. First Art: Art Experiences for Toddlers and Twos, by MaryAnn F. Kohl
For out of the house, we've also enjoyed the classes offered through the parks and rec department. They're really affordable, and you can find classes for music, dance, gym, and such to help get those wiggles out.
Good luck with your high-energy little guy. You must be tired!
Take care, Juliet