Assault

In an assault map, there are several objects placed. Only one of them is active at any given moment. The one which is active must be destroyed before the next one can be unlocked. The round ends when the last object is destroyed or the timelimit is hit. After the round, the defending team attacks and the attacking team defends. The ultimate victory belongs to the team that destroyed the objects the fastest.
Assault is likely the most obscure game mode there is. There are little to no maps for it, and none shipped with nexuiz. There are very few servers running it.