[SGCOS]

Here's a couple from the RAT tongue twister book:

Tax cuts are good.

Socialism is an utter failure.

Less dependence on the government is a good thing.

[Siegfried]

Here's a variation on the pheasant plucker one:

=======================
I'm a pheasant plucker.
I pluck mother pheasants.
I'm the pleasantest mother pheasant plucker
that ever plucked a mother pheasant.

=============
After you get the hang of it, it's great to challenge your drunken buddies to try repeating it after you!