Well, you can:
Lay on the floor*, wank, sit, Thai Chi, Grab a beer, Smoke

*Some or all of your health will be restored
Your fighting style will become the same as it is in San Fierror(some kinda Karate/Tae-Kwon-Do)

Credits:
2pac_96 - For the idea
LybertyCityStories - For the BG version
FireStone - For some of the pics

GTAF topic:
http://www.gtaforums.com/index.php?showtopic=399600&st=0&#entry1058998677