DoD might be fun. I've had a few decent games fooling around with it before. RC2... negative, unless there's a way to turn off the rocket launcher weapons. If so then very much yes. It's a great game with a lot of fun in it, but the stupid rocket launcher weapons, which are all proximity based, are just silly. You can seal off a whole area of the map just by spamming mines and turrets and junk all over the place. Of course, the exploding scientists and barneys are still cool...
I've played hostile intent a bit, and it's a lot of fun, but it is still awfully buggy, and not very widely played.
For fun mods that probably wouldn't last too long: Bumper Cars and snow wars are two classic favorites. We might also consider a zombie panic server... but probably only after the game gets out of playtest phase, which may still be a ways off.