Cartoon Network has launched its browser MMO, Fusion Fall. You can sample the game for free at the Fusion Fall website.
With a time-travelling storyline involving Dexter, Samurai Jack and other toons from the popular kids' channel, Fusion Fall seems aimed squarely at tweens. You can play the early levels for free - after that it's USD 5.95 a month, or USD 9.95 for a "family plan" including four accounts.
Fusion Fall is a full 3D game with a colourful, cel-shaded, platform-game look, but it launches pretty swiftly in a browser window. If you're older than 12 it will mostly be of interest for checking out the impressive Unity web platform. Or meeting Samurai Jack, who is awesome.
The login process assumes you live in the US or Canada, but there seems to be no blocking of international IP addresses for now, so players elsewhere can sample the game. We haven't tried setting up a paid account, however.