When Someone who usually has nothing to do, usually because they're unemployed, suddenly has something to do for that day. That one thing, no matter how meaningless becomes the big deal of the day.
Used to sarcastically act like you aren't trying to brag about something that isn't worth bragging about. Should make it seem like you are bragging about it. Usually said in a sarcastic tone. Not to be used when something actually is a big deal.
Starbucks lady: "Total is $4.23"
Me as I hand her $4.23: "Exact change, no big deal"
or
Girlfriend walks in, me on the computer
Me: "Just checking the spiderman forums, no big deal."
The opposite of a big deal. The go-to catch phrase whenever you are presenting something in a humble light. This phrase is not sarcastic in any light and should never be confused to mean a big deal. It is by no means a big deal whatsoever, no big deal. Also not to be confused with yes big accord.