I go with the drink anything, don't drive. If you can't feel your tongue anymore you're probably watching the Bills, and should stay in the stadium or your living room for the duration.
It might tell you your BAC, but that's not really a good indicator of how drunk you are. Still, it would be an interesting novelty; not for the price, though, I'm sure.
[–] pyres ago
Many people also have the fun option of a built-in breathalyzer in their vehicle once they've been caught once.