This is what I do at work...looking up tongue twisters on the internet is actually job-related for me. Of course, I would never dream of giving this one to my students. The ones I wrote down for them were like "Six sick sheep" and "Toy boat toy boat toy boat." (That last one is trickier than it seems like it would be.) The one below cracked me up. It was also one of the few ones with words starting in S that didn't end up with me accidentally cursing.
Ned Nott was shot
and Sam Shott was not.
So it is better to be Shott
than Nott.
Some say Nott
was not shot.
But Shott says
he shot Nott.
Either the shot Shott shot at Nott
was not shot,
or
Nott was shot.
If the shot Shott shot shot Nott,
Nott was shot.
But if the shot Shott shot shot Shott,
then Shott was shot,
not Nott.
However,
the shot Shott shot shot not Shott --
but Nott.
PS - While looking in the little library at my job today I found a book so bizarre and hilarious, I'm going to take a picture of it and post it later on. I removed it from the library, amid head-shaking and the thought, "This is what happens when non-English speakers buy the books for the library." So there's something for you to look forward to.