I freaking pwn you

Summon your inner geek (go ahead, I'll wait) and enjoy these extremely 133+ plates I've hand picked for you today.

PWNZ GAS is from Colleen S, who informs me this was on a Toyota Prius (a hybrid). According to wikipedia, pwn is a leetspeak slang term derived from the verb "own", as meaning to appropriate or to conquer to gain ownership. The term implies domination or humiliation of a rival, used primarily in the Internet gaming culture to taunt an opponent who has just been soundly defeated (e.g., "You just got pwned!").
We must thank our RPGAMERs for such a s00perb linguistic dialect. RPGAMER was snapped by Squidrox. I like how this person is so proud of their nerd-dom.
PWNNOOB is from sara-liz. A n00b, according to the urban dictionary is an inexperienced and/or ignorant or unskilled person. Especially used in computer gaming. So basically, this person is stating something like:

"Sir, I dominated you based on your lack of experience in this particular skill, specifically, driving. Now use your signal, and kindly remove yourself from the passing lane." kthxbye.