The chemical reaction within your skull caused by an amazing, revolutionizing, bordering on orgasmic, revelation - often related to a very nerdy subject (but not always, as seen in the example). I.e. a meltdown of the brain. More intense than mindblowing.
Guy 1: Hey dude, I heard Chuck Norris can divide by zero..
Guy 2: OMFG! *brainplosion*
Guy 1: Dude..?
Guy 2: Gaahhh.. *drooling*