An exclamation used to describe either the positive, or negative extreme on the 'awesome scale'.
Or something both positive and negative simultaneously
Positive: "That scythe is so balls!"
Negative: "Aw, BALLS! My car ran out of gas!"
Both Simultaneously: "You kicked that ball from all the other side of the field and hit me in the face! That was balls!"
Guy 1:Wanna hear a joke?
Guy 2:Sure..
Guy 1:Why didn't the clown juggle at the circus today?
Guy 2:I don't know Guy 1:Because he didn't have the "balls" to do it.
Guy 2:Mom you can't make jokes..
Guy 1 (mom):I made you.
Guy 2:Fuck you
Guy 1(mom):I will