Maybe you already saw the plenty of ads everywhere about GarageGame's new gaming portal called InstantAction. I think it's very well done. Most of the site is HTML – only some areas do require flash and of course the games are using an extra plugin. Installation of that plugin in firefox was very smooth – very nice with pictures for each step. The website design is trendy and makes it already stand apart, but also the fact that you can quickly play multiplayer 3d games in your browser – after registration and installation of the plug-in.
On the negative side I found, that after downloading a new game, the process does often hang. Leaving and rejoining the game fixes it. I also had to give internet-connection rights to each game separately. In addition to that, in the lobby you don't see ping times thus lag or disconnection might occur often in some matches. If you want to try it yourself, I'll suggest "Marble Blast" or "Think Thanks". The others are less interesting. A Tribes-Like title is announced called: Fallen Empire Legions.
As we are talking of GarageGames, there is maybe something else interesting especially in regards to the topic of one of my recent postings. They have a 2D-Game Authoring environment called TorqueX Builder. It's layered upon their for their new XNA based engine called TorqueX. They now announced that they added 3D support on the engine level – the editor will be 3D enabled in the future. TorqueX allows deployment on Windows and Xbox360.