By the way, I've had many gnarly shots (many of which are listed here... working at a bar has it's pros and cons), but of any shot, my favorite would have to be the Duck Fart.
Duck Fart
-Baileys Irish Cream
-Kahlua
-Crown Royal
Combine equal parts of Baileys and Kahlua into a shot glass until 5/6 of it is full. Top with Crown, shoot, and enjoy.
It tastes quite like a caramel Frappuccino and is especially delightful between shots of Jack.