This is not something I learned from Johnny Knoxville.
A few years ago, Eric found a simple recipe for habanero tequila: chop up three habanero peppers and slip them into a bottle of tequila. Chill for at least three hours and enjoy. That's it. Even if you don't like it when your mouth feels as if massive flames of fire are being emitted, taking this to a party will be far more memorable than a 2009 Argentinian Malbec. (Note: I will not be offended if you bring a 2009 Argentinian Malbec to my next party.)
A warning: if you have one shot, you will want another. Once you stop feeling as if your head may pop off your body, a seemingly reasonable thought will occur to you: I could really go for another shot. Despite the irrationality of this thought, you will do it: you will have another shot because the tequila and habanero mixed together is just that good.
As for choosing a tequila, I have found using a good tequila rather than a cheap/subpar tequila is the better way to go. My favorite these days is el Jimador (blanco).
Happy (and responsible) drinking all!