"I don't want to teach a grandmother to suck eggs."

I'm going to live forever - or at least, die trying.

How about a "stick in the mud" -- means someone who is practical and ruining everyone's fun.

(A bit ago, I offered to go over American/English idioms and have some in another thread: http://www.italki.com/discussion/102329. Let me know if you'd like more.)

You are so skinny you have to run around in the shower to get wet ;)

All bark and no bite

Let the cat out of the bag=(means) to reveal a secret carelessly or by mistake.

To be green with envy.

To give someone the air( don`t use it every where.it`s vulgar)

:)