Question

What is a cliche and what is a sentence that's an example?

Answer 1

have your ccake and eat it to.

Answer 2

http://www.thefreedictionary.com/Cliche

http://en.wikipedia.org/wiki/Clich%C3%A9

http://grammar.about.com/od/c/g/clicheterm.htm

Answer 3

Here's some examples:
Time heals all wounds.
When you have lemons, make lemonade.
What goes around comes around.

Its basically something that you hear all the time. They are a popular form of expression :)