Fun & games at becomeanmm.com: first, create a character for yourself. Mine's above.

Now, how long till can I use this little guy as my Second Life avatar??
Once you've created a character, you can use M&M partner Zazzle's service to put it on hats, shirts, etc.
The M&M site also includes a fairly basic World (pseudo-virtual - just a bunch of images you can click on, no real navigation or experience); and a couple of Flash games (couldn't get these to work on my visit).

Also fun is the ability to insert your character into a little Flash movie:

Link