In Irish history and folklore, as well as that of other countries (including the US), cursing contests have been recorded. In Patrick Powers' "The Book of Irish Curses" (p.22, Mercer Books, 1974) he supplies this example from County Fermanagh:

Willis: May your hens take the disorder and your cows the crippen, and you calves the white scour! My yourself go stoneblind so that you will not know your wife from a hay-stack!

Murphy: May the seven terriers of hell sit on the spool of your breast and bark in at your soul-case!

I've seen some now-deleted threads that indicate that 'Catters are good at name calling, but I've long wondered if true cursing isn't a lost art.

So here's a chance to demonstrate otherwise. Pretend you've got someone in your sights (GWB, Tony Blair, GUEST, John Kerry, Bill Shatner, you choose your favorite) and blast 'em with a curse that will shrivel 'em up like a raisin in a dry wind. But -- you can't use any of the "seven words you can't say on TV" because they're so common they've lost their effectiveness. You gotta be creative! And name-calling isn't cursing, so if you're going to call someone names, put a curse in with it.

Here's another example from Powers to get you thinking. The whole thing is on page 87.

A Mháire Ní Dhúinléith, go n-imí ort!
Páiste trasna ort agus nár bheire tú coíche é!

Oh Moll Dunlea, may harm overtake you!
A child be within you, for ever unborn!

Go for it. Try to be creative.