Hostile-Planet.com
I think it looks pretty cool, it's an MMOFPS/RPG similar to Planetside for Half-Life 2. The mod is still under development so don't expect it to be out anytime soon but, it looks pretty awesome in my opinion maybe being as good if not better then Planetside. The only problem is that people will have to play it to for it to be good and game mods usually only get a couple hundred people online at a time.
And unlike most mods, Svencoop, they are actually making a lot of progress, they just did a mini-mod called King of the Server to make sure that their server-database program worked to save stats but, that's down now.
The mod is also going to be free especially if you get one of the first accounts, later they might make you pay for it if a lot of people join and they can't keep the servers up with just donations.
So just bookmark the site if you're interested, the people that sign up now will be more likely to get to beta test it first.