Here's one I came up with recently. Go to Bing Translator and type in a snippet of a favorite paragraph, poem, or play. Translate that snippet into another language. Then translate the resulting translation back into English.
Alas, Poor Yorick.
I knew him, Horatio.
A fellow of infinite jest.
Alas, Yorick pobre.
Le conocía, Horatio.
Un compañero de la broma infinita.
Wings, poor Yorick.
It knew him, Horatio.
A companion of the infinite joke.
How much wood could a woodchuck chuck if a woodchuck could chuck wood?
...transmogrified into Japanese and back becomes...
As for the woodchuck which when the woodchuck can install the wood with the chuck, is possible to install which rank wood with the chuck?