A bitter biting bittern
Bit a better brother bittern,
And the bitter better bittern
Bit the bitter biter back.
And the bitter bittern, bitten,
By the better bitten bittern,
Said: "I'm a bitter biter bit, alack!"

Mr. See owned a saw.
And Mr. Soar owned a seesaw.
Now See's saw sawed Soar's seesaw
Before Soar saw See,
Which made Soar sore.
Had Soar seen See's saw
Before See sawed Soar's seesaw,
See's saw would not have sawed
Soar's seesaw.
So See's saw sawed Soar's seesaw.
But it was sad to see Soar so sore
Just because See's saw sawed
Soar's seesaw!

How much wood would a woodchuck chuck
if a woodchuck could chuck wood?
He would chuck, he would, as much as he could,
and chuck as much wood as a woodchuck would
if a woodchuck could chuck wood.

My goodness!  Some of these are quite long!  But they're still a lot of fun!  How about:

Theophilus Thistle, the successful thistle-sifter, in sifting a sieve full of unsifted thistles, thrust three thousand thistles through the thick of his thumb.

seven swans swimming swiftly saturday[size=4pt] _{made this one up}[/size]

kick ken kite