There is a really fun browser-based, Halo-themed RPG game called HaloSphere 2.
It is created by the founder of HaloCharts.com, which (until its recent closure) was the biggest Halo stat tracking website around. It’s a lot of fun to play if you’re sitting in class or at work, or just watching TV. There are TONS of Halo fans to talk to in the chat boxes and forums.
I’m not in any way affiliated with the site other than being a huge fan and a consistent player. Feel free to shoot me a message if you have any questions