OOC is shown in a couple of ways, commonly with a label or as double brackets.
((Can I say something for a sec?)) or
OOC: Can I say something for a sec?
OOC's antonym is IC, or BIC-- "In Character" or "Back In Character."
OOC:: the magical stone was still there when we left it right?
ooc; So should I bring in adrentie now? whos turn is it?
ooc; I have somuch museee!
mike- yeah you OOCing out last night, you were hitting on some bouncer's girlfriend and when they threw you out you started throwing snow balls at them.
paul- why didnt you stop me?
mike- I tried but you were too OOC'd out, i just had to let you learn the hard way.
paul- i think i got her number