leet is like ebonics.. except for gamers.
to put it in context:
"1 pwn3d j00 nub!! heahhehhahahhahah!11!!!!! w00t! w00t!!!1111 br1ng b4k dat sp1tz$!*@$!! g10 r0xx0rs ur b0x3rs!"
That would be a simple declarative sentence, stating I just shot down someone in a spit, whom I then declared a newbie. I also asked for them to come back so I could kill them again. It also loudly declares the dominance of the Bf109-G10.
Now, if somebody could just find the person that invented "leet speak"... put it all in a gun, and put it in his brain...