Anyone who has played an RPG like Mass Effect would know what I mean. Stuff like hacking computer consoles, or lock picking like in Alpha Protocol. Mini games where the player has to complete certain objectives to gain access to weapons, ammo, money, intelligence, etc.
Would work really well in single player, but also in multiplayer perhaps for team based games where an objective needs to be carried out.
-Hack the enemy computer
-Sabotage the enemy computer
-Setting up a beacon
-Acquiring new objectives
-Setting up explosives for detonation
There is nearly an endless list of possibilities for mini games.
On successful completion of mini games for example in multiplayer games you could have rewards, similar to the killstreak rewards in Call Of Duty, you complete the mini game successfully you earn he ability to control a homing missile or bombard the area with artillery. So many ideas exist.