A Spock Jock is an uber nerd, they are typically rational and intelligent. Their favourite novels and films are about space and their T-Shirts have sayings on them or retro gaming consoles.
Friend 1: I don't know how to describe Natalie, she's like nerdy to the power of awesome.
Friend 2: so a Spock Jock then?
Friend 1: Hell yeah, live long and prosper.