I have played with:

FaZe Trick (got invited to his game)
zzirGrizz
OpTic Pred OG(played him a Private Match)
OpTic Jewel (got invited to the game by her friend)
and more people!

They are all known for sniping in COD

the games i played with them in:

COD 4
COD MW2

ive played with members of roosterteeth gavin,caleb,fragger and ray i also played with bigbstatz he does minecraft xbox 360 vids

I Played the hidden source with SeaNanners, Hutch and ChilledChaos, LOVE THEM SO MUCH

TTG SEAN if he is considered known. I've been in a few games with some known OpTic's too.

i've played with TreTzy or also known as Lispy Larry

I have been in a priavte match (mw2) with ArabModderOsama which is the infamous hacker Teh 1337. He proved it by telling me to go to one of his videos and looking at a comment he posted saying the clan tag and title he had in mw2. I later on saw a recent black ops 2 video of him recording his mods on XBLS Osama and when he was signing in I saw the gamertag "ArabModderOsama".

I'm just surprised since he is a very well known coder for gaming and certain programs.

Might not be as interesting to most of you but that's the most interesting person iv'e met on xbox.

I've only played with a couple popular Gears guys like ArCtiC zYn, Skyllus zYn, and Kaos Advocate. Other than that, I ran into Snip3down in Halo 3 if anybody still remembers him from long ago.

Some peter griffin. XD

Serious bro.

I have played with Minnesota Burns - Basically he trolles kids on XBL - the account i added him was ImNotBurnsy funny guy

mine would have to be DudeImGodly and BAD KID on BO1. DudeImGodly is a well known youtuber and BAD KID IS a MLG pro i think. They were in the same lobby