I'll start with a few that I've heard.

Zilean bombs "BOOM SHACKALACKA" over and over. This was before he actually got the kill mind you

Pantheon (while channeling) "It's rainin men, hallelujah!"

I said this one, I thought it was funny.(Don't judge)
Shyv (Ultis in for a triple kill) "Been playin quite a bit of skyrim lately"

What are some you've heard, or said? I like to hear em =D

Cannot think of any off the top of my head but I did get a cross map kill the other day by saying Ashe? Yes? *fires off ulti while ashe is typing*

Me: Who ordered the whoopass fajitas!?

On ezreal

i think the funniest was

"tag your it"

singed has slain an enemy

Mine has to be Shyvana ulting out, and saying in all-caps- FREE WILLY

Volibear scores a triple kill. "The sign clearly states, DON'T FEED THE ANIMALS!"

All good stuff! Keep em comin =D

Playing Pantheon, ult into enemy team. Target enemy Shaco. After dealing a fair amount of damage to all of them, almost killing Shaco, and then dying my team comes in and teamfight ensues, my team winning fairly easily. Shaco, not seeing that my friend had oracles, stealths and tries to place a box

BOOM!
.
.
.
.
You have been slain.
An enemy has been slain.
Double kill.
Triple kill!
Me: My death was totally worth it.
Quadra kill!
Shaco: Mine wasn't....