I saw Esau, sitting on a see-saw,
I saw Esau, he saw me.
I saw Esau, sitting on a see-saw,
I saw Esau, he saw me.
I saw Esau, he saw me, and she saw I saw Esau.

(ed: while ostensibly a 'tongue twister' it is also a trick question. The idea is that you recite the poem then ask the 'victim', "How many s' in that?" And when they come up with a number you should "No! There *are* no s' in THAT." - well ok... but kids like it :))