Tongue Twisters

In a poorly written piece over at Boston Magazine we have An MIT researcher purportedly coming up with the most difficult tongue twister yet. Only it's not. Try to "annunciate"--as I said, poorly written--this:

Pad kid poured curd pulled cod.

As the commenters mention, there are far more difficult tongue twisters.  And more fun, too. They provided some good ones.

I'm a mother pheasant plucker, 
I pluck mother pheasants. 
I am the best mother pheasant plucker, 
That ever plucked a mother pheasant!

The big black bug bled bright blue blood.

The sixth sick sheik's sixth sheep's sick.