Oh man you asked for it. When I played rugby we did some sick circuit routines that seriously left you wanting to lay down and puke. I can't reveal the secret details of the torturefest but it involved doing as many bodyweight excercises as you possibly can in cycles, with almost no rest. So an example would be:
Pushups: 1 min, as many as you can do
20 seconds rest
Situps: 1 min, as many as you can do
20 sec rest
Calf-raises (easy for a reason): 1 min
20 sec rest
Jump squats!!! Like squats but faster, with a jump at the end. This is the crux of the cycle... 1 min
20 sec rest
Back raises 1 min
20 sec rest
A timer is helpful.
The heart of the routine: repeat 4 to 10 times, or until you vomit! NEVER rest for longer than 20 seconds, even when repeating the cycle.
Bonus excercises you can throw into the cycles:
Pullups (if you have a pullup bar)
Dips
Stairs...
ps. if done right, most of your body will be in excruciating pain the next day!