Nothing new here, but my wife reminded me of a few of the best lines that got said during some sessions of WFRPG:
By our Veteran after decapitating a Khornate Cultist with an axe: "Yum, tastes like Blood Flavored Corn Syrup." Of course it has been called Khorne Syrup ever since.
Same Veteran in a pit fight to his random NPC dwarf partner: "Need a hand?" This was right after saving the dwarf's from a backstabing foe. Only problem was that the Dwarf had lost both hands while an Orc captive and fought with iron beer mugs strapped to the stumps. The dwarf promptly began to attack our Veteran.
In 7th Sea a duelist played by my brother was punched by an NPC who rolled all 1s for his damage roll. He responded with "You hit like your wife. And yes I WOULD know!" He also rolled incredibly well for that taunt roll.
In Shadowrun I was playing an Orc Private Eye named Gar Cooper. He had no magic or cyberware and thus was vastly inferior so I had to adapt to each situation using his skill and wits. He was trying to protect a witness so he told her to come with him and she would be safe. I decided that rather than take her through the firefight I would shoulder charge through an interior wall between the studs and make a new doorway. Right as Gar began to charge into the wall our PhysAd face Dash Magnum(a human action movie star with magic to boost his charisma and social skills but no practical combat abilities) turned on the magical charm and ended up rolling a 64 on a single six sided die (each 6 rolled allows an additional roll which add together). Everyone in the room turned and stared. I managed to make it through the wall still, but hit a stud and dislocated my guy's shoulder.
I know there was more, but I can't remember all now. I'll add more as I remember.