This is kind of random, I found out that you can play Quake from your browser for free 🙂  I can’t say I’m very good at the first person shooter games…but it was fun trying it out.  It’s in full 3D and you get to connect and play with other people online.  It’s pretty simple game-play, you pick up weapons and buffs and try to shoot everyone else before they shoot you.  They do have a few special modes like – team play and capture the flag.  You don’t need to download and install a full program, but you will need to download a plug-in – then you can play it straight from your browser!

It wouldn’t work in chrome at all, but I was able to install the plug-in and run it fine in Firefox.

http://www.quakelive.com/