Doing a bit of background I stumbled across this nice collection of military humor. Some I'd heard of, some I hadn't, but I haven't seen any of it all in one place like this before. Includes a Tasteless Joke^tm my mom just sent me:

A Mexican drinks his Tequila and suddenly throws his glass in the air, pulls out a pistol and shoots the glass to pieces. He says "In Mexico our glasses are so cheap that we don't need to drink from the same one twice."

An Iraqi obviously impressed by this, drinks his camel beer, throws his glass into the air, pulls out his AK 47 and shoots the glass to pieces. He says "In Iraq we have so much sand to make the glasses that we don't need to drink out of the same glass twice either."

A US Marine, cool as a cucumber, picks up his Miller Lite and drinks it, throws his glass into the air, pulls out his M-9 Beretta and shoots the Mexican and the Iraqi.

He says "In America we have so many Mexicans and Arabs that we don't need to drink with the same ones twice."

Which is a variant on what is probably an Iraqi-developed joke. No-prize to the first person who finds it.