At the end of a arm workout, curl-ups w/ parallel bar dips. 3 quick sets to failure gives me a unreal pump. On the curl-ups I change the grip on each set. Close-grip underhand, close-grip parallel and close-grip reverse. On the dips I usually perform them with my back towards the dip bar and keep my elbows tucked in with my body upright.
Anything worth having is never easy to achieve.