Yesterday, I was in a Japanese online game (囲碁) forum and before a game started an opponent asked me:
あんた、マジできる?
I only know マジ as a colloquial way of emphasis, so I couldn't figure this out. Was he asking me if "I'm any good"? It also turned out that he was very bad at the game - to a degree where he probably didn't know the rules. Maybe he was asking me if I knew how to play?
Can someone please explain how the マジ fits in there?