Pronounced: OH for five six! Said in place of the profanity "Oh, for f@ck sakes!" This originated back in the 1970's early 80's, I believe. See also Profanity.
See also Teenagers.
Gareth Keenan's answer to the question, "What are you thinking?" See also British.
Next time you're a guest at someone's house, ask this. As seen in the recent movie Nebraska. See also Bathroom.