The Apocalypse Now is not a shot for the faint of heart or people with sensitive taste buds. The mixture of Irish cream and tequila is an interesting combination in itself, and when you add dry vermouth to that it gets really interesting. If you are looking for a quick, potent novelty shooter, this would be one to try.
You can also make a drinking game out of this if you're watching the movie Apocalypse Now: something like a round of shots at every mention of the infamous Colonel Kurtz. You could get really drunk off that game, so brush up on your hangover cures and don't drive.