I don't really like to sit too long at the drum set and play nowadays, unless I have something I really need to trash out. Usually I set my metronome on at a comfortable pace, sit down for 30-45 mins and just start off with some basic rudiments (RLRL, RRLL etc etc) then go onto loosening up my arms by doing fills and stuff. Then maybe rest for 10 mins or so, check email, play some progression on guitar then after that it's back to the drum set to try and find a beat that fits the progression. If cannot then it's about 30 mins freestyle-anything-goes 'solo' and just whack some random stuff that I can think on the fly. Rest and repeat when the urge comes to smack some skins.
On the other hand, if I have a jam session coming up, it's head phones on and play along with the song. Quite fun actually.