Plan of Attack is the first original and viable mod for source not put out by Valve. You can visit there web page here: http://www.planofattackgame.com
It's a round based objective motivated game, similar to cs. Each map has 3 objectives. The two teams take turns attacking or defending. The attacking team has to pick which objective they will capture before the round starts.
Objectives give your team money and experience. The game is class based, like firearms, but not as detailed. As you go up in level your player gets better bonuses on your in-class skills.
PoA is the 5th most popular third-party game on steam (behind ns, specialists, esf and sven co-op). It is by far the most popular third party hl source mod. The last release includes xfire support. At the time of this writing, there are over 10,000 players. Clans are forming now, and competetive play is ramping up. This mod is not a passing fad. The first beta was released 28 Apr, and the second 23 May. 10,000 users in a month. It was 9,000 yesterday

I would really prefer not to have to go to another vendor for a server. NFO has superior support and quality unmatched in the game server market. Will you look into it?