OpenArena is an open-source content package for Quake III Arena licensed under the GPL, effectively creating a free stand-alone game. You do not need Quake III Arena to play this game. Bots were added starting in 0.6.0. They will spout taunts and everything! Concepts would be loose, so don't expect a remake of Klesk in his original Klesk form, or any direct remakes of any map/weapon/model.
Fast automatic download feature for getting extra stuff required to play on specific servers (automatic download option is disabled by default, considering that such extra stuff may not comply with GPLv2).