I love football theory. While I never ran some of the more exotic systems (such as the "single wing"), they are a blast to watch when they are executed properly. The NFL is constantly evolving (such as the turn from FBs to TEs), and nowhere is this more obvious than in Miama, where a "terrible" team is taking some plays from the future and confounding the "elite" teams of today.
The Wildcat is an option based system, and (like the single wing) features no QB. Unlike the single wing, we have two WRs. While a critic of ESPN, I want to credit them for putting up Gary Horton's excellent breakdown of the Wildcat. It's instructive, includes some nice animations, and is just plain well done.
Here is the article on the scheme.
Here is an article on the counter.
And here is a look at which current NFL teams can run the program.
As always, feel free to leave any questions about the WIldcat, or any other X's and O's questions in the comments thread. Remember, Mile High Report University will be returning to the front pages after the season concludes.