At a Cyberpunk game, concerning an overhauled vehicle with obvious weapons systems:
Andrew, aka Diego: "This is how Nature says, "I'm gonna mortar your ass!""

At another Cyberpunk game:
Nameless:  "Ug.  Me hungry.  Me get food.  Oh wait, I'm talking like a solo."
Aleena:  "Hey, I resemble that remark!"
Felix:  "Yeah, say that again to my assault rifle."

Zortech:  Melee weapons for a more enlightened age.  - Ryan

Nutscrape Navicrater or Microshaft Exploder?  - attributed to Mark and Marten

Russian proverb:
The genius points to the sky - the idiot stares at the finger.  - Julia

Concerning a picture of Xena: Warrior Princess:
Merv:  Why do they have her holding a staff?  Doesn't she usually have a sword?
Richard:  It's for comfort.
Mark P.:  Days on Argo must be long.
(If you don't get this one, it is not my fault.  Not my fault, you hear!?!)
 
At a Cyberpunk game:
Jimmy:  "Look, I'm sorry."
Felix:  "Sorry.  That's an expensive word."

Mud spelled backwards is dum.

Me:  "Boys are dorks."
Dan:  "I'm not a dork, I'm a pervert.  I get some."

Dan:  "Get a loan.  Buy a clue."

After lots of bad scot + sheep jokes (good natured, of course):
Andrew:  "You can't pull the wool over my eyes."
Julia:  "Not at that end, you won't."

At a roleplaying session:
Chris, aka Dirk: "What do you get for a 10 month old that obviously has everything?"
Joy: "A therapist."
 
Meisha:  "She who dies with the most sugar WINS!"
 
On whiteboard at work:  "Maps rule - cartographers drool"

"You know, silence can be a learned response . . ." ". . . Or an inflicted condition."  -Dan and Chris, respectively.