Whenever Teemo killed an enemy he would say
"Tiny Teemo balls, in your mouth, like little raisons."
The enemy Teemo tried to copy him, but our Teemo responded
"Ew are you gay or something??"
I rofl'd

My friend playing as pantheon dives a tower and types in /all and yells in vent BRING THE RAPE!!!! didnt notice the Cho-gath who was mid-teleport, who then subsequently ate him. /aneurysm engaged

Raging enemies calling me a noob.... my response?

Try knitting, puss.y.

Or another personal favourite is getting killed by a fed player and shouting: YOU AINT AFRAID OF ME!

Amumu chasing a friend

"Stop crying on me you emo sob"

an enemy teemo was sitting invis by dragon and stole it from my team
team: HOW???
teemo: patience young padawan

afterwards he explained he had been sitting there for 6 mins

my friend on vent(panth) was like
imma towerdive these 3
me: thats crazy
friend: crazy ... crazy... THIS IS SPARTA
me: ow ****
*fails*
me: told you
friend: at least now i dine in hell

lol'd so much

I was playing as Caitlyn during a 3v3 when a team fight broke out in the top lane, at this point we are all lvl 18 and during the fight my 2 teammates die as do 2 of the opposing players. The last one, Kassadin runs away into the bushes and has flashed around into the middle jungle to avoid me (he has 100 health or so left and I'm at full).

At this point my teammates start complaining as I try to shoot Kass with my Q

Teammate: /all "OMG CAIT NOOB CAN'T FIND KASS!!!"
Me: "I'm trying to find him!!"

*Trap triggers and I snipe him now I know where he is*

Teammate: "NICE!!!!"
Me: /all "Found ya =)"
Kass: "FFFFFFFFUUUUUUUUUUUUU"

Stands out in my mind =p

"Well we technically won"

in an ARAM after getting aced at the nexus and losing their own base.