Sega has launched their new gaming/social networking site PlaySega.com, which features flash games (such as Sonic at the Olympic Games sans-Mario) and customisation options. The customisation options can be bought with the rings you earn from playing the games, with things like avatars and "chalets" on offer.
Currently there are only a few games, but Sega has said that another thirty will be added soon. I have already signed up, and I am sure the site will be great!
By the way, make sure you put "www." in front of "playsega.com" or else you will go to the Phantasy Star Universe site!