Welcome to the Warrior caste, otherwise known as manly men whom must prove their manliness by whacking each other with what ever comes to hand. There are some well documented sociological studies that suggest a link between behavior like that shown on Jackass (which while extreme similar behavior is very common) and a lack of regimented initiation rights like those seen in tribal situations, and ritual outlets of aggression. So the guys from Jackass are really just acting out cause nobody will let them joust 
Time to bring back jousting then!
