a. Something that is logically bad-ass
b. Stems from two words: Spock and Rockin'. Spock, who is a Vulcan in the extensive universe of Star Trek, is a most logical alien-man. You may know him to be played by Zachary Quinto in the most recent rendering of the kick-butt, sci-fi movie. The guy with the awesome bowl-cut and pointed ears? Yes, that would be Spock.
Rockin' is used to describe something that is very awesome. So awesome that it cannot be simply described by the mundane word of "awesome."
c. Together, you have Spockin.
"Dude, Frances named her car the Enterprise! That is Spockin!"
"Dude, that was a Spockin study session!"
"Dude, that documentary on how squirrels are actually inter-dimensional beings was Spockin!"