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!