Tongue twisters

Tongue twisters are words or sentences which are difficult to say.
Here are some famous examples:
- She sells sea-shells on the sea-shore.
- Peter Piper picked a peck of pickled pepper.
As you see, tongue twisters very often have words which start with
the same letters.
Write some tongue twisters of your own. You get a point if
your teacher can't say them without making a mistake!