Ok guys this may not be for all of you but here's what I find most effective for getting those stumps super pumped:
(only use this program once a fortnight due to it's intensity and huge impact on your CNS)
Leg Curls, for the pre pump - 2-5 reps at light weight followed by 25 reps X8 at maximum weight (special technique my uncle taught me)
Donkey Raises - Same rep range
15 Star Jumps (if you aren't already exhausted)
And for the rest of the workout I concentrate on doing more important things like biceps this helps to get a good blood flow to the femoral artery obviously resulting in ridiculous stumps.
This part of the exercise usually involves super-setting of preacher curls & swinging DB curls (standing for maximum swing)
This may sound a little unusual to some but the pro's will understand.
Just ask my uncle Pasquale!!