theory11 — Magic Tricks & the World's Finest Playing Cards

The spinning card of doom!

It's known as the Martin Lewis spinner or index finger propulsion. I'm not sure where it's originally described, but it can be found on The Art of Card Throwing DVD by Rick Smith Jr, in Cards as Weapons by Ricky Jay (if you're lucky enough to find a copy), and in the Encyclopedia of Playing Card Flourishes by Jerry Cestkowski.
 
It's known as the Martin Lewis spinner or index finger propulsion. I'm not sure where it's originally described, but it can be found on The Art of Card Throwing DVD by Rick Smith Jr, in Cards as Weapons by Ricky Jay (if you're lucky enough to find a copy), and in the Encyclopedia of Playing Card Flourishes by Jerry Cestkowski.
I stand corrected :p