The nerd equivalent of adrenaline, a nerdrenaline rush is when a nerd, geek, or dork engages in an activity that stimulates them in ways that only nerds truly appreciate.
Nerd #1: Dude, the ending of Star Wars Episode VI always gives me a huge nerdrenaline rush.
Nerd #2: Yeah, same with me. That, and the Discovery Channel.
Nerd #1: Totally.