Methylphenidate (Ritalin) and the amphetamines do wonders for physical work. You feel fantastic and capable. Amphetamines in particular provide a bit of a euphoric boost. In general, amphetamines are going to make you feel pretty damn good, although coming down might be unpleasant sometimes.
I have to caution people to not do exert themselves, as they figure out that they can go workout at the gym like mad. I'm not sure it's healthy to work out while on stimulants.