The Dark Times is a Star Wars Battlefront II mod with a heavy single-player focus. It adds many new features to the game, including (but not limited to!) wave modes, randomized units, heroes, and skyboxes, and AI hero support. Its sequel, Rising Son, adds more of the above as well as several new maps and scripted missions.
This, along with Ultimate Battlefront: The Clone Wars, is the best mod for Star Wars Battlefront 2 out there. If you have a copy of the game, get this mod. Just get it. No excuses, get this mod. The gameplay, the graphics, everything about this mod is spot-on, and on par, if not better, than the original game.