...Canada, and Australia. Let's have some fun with this; the more colorful and funny the expression, the better. Please be specific about the (possible) origins of the expressions you submit, as well as the meanings.

Let me begin....

God didn't die and leave you in charge (NYC and vicinity): said to someone to remind them that they don't run the show.
Fuhgeddaboutit(NYC) - never mind, no problem, you're forgiven, etc. A catchall phrase.
Not for nothin', but.. (NYC) - a way to tell someone an unpleasant but necessary thing in order to take the sting off it. Example: Not for nothin', but I think you need to hit the shower instead of telling that person he or she stinks.
Get outta here! (US) - You're kidding me. This can't be true!
I wasn't born yesterday! (US national) - I'm not an ignorant teabagger Repuke, so stop lying to me!
My birthday is (insert your b'day here), not (yesterday's date) (my own!) - a variant on "I wasn't born yesterday"!
Hotdogging (US) - showing off
No comments from the peanut gallery! (US) - Unsolicited opinions are not welcome

Anyone else care to add to the thread?