lmfaopimprotfl
l-laughing
m-my
f-fuckin
a-ass
o-off
p-pissin
i-in
m-my
p-pants
r-rolling
o-on
t-teh
f-floor
l-laughin
basically a term to express sarcasm over someone
or to express emotions when you find something real fuckin funneah. ;)

1st leet player:zOMG, teh newb died from a low level mob!
2nd leet player:LMFAOPIMPROTFL