Mad Keen - Mad keen is when you're so ready for something, you're like

Mad keen is when you're so ready for something, you're like a kid on Christmas morning, but with more profanity and less patience.

I'm mad keen on this game, I'm already cheering before the first round even starts.

She's mad keen on this drink, she knocked it back like it was a curse.

He's mad keen on this fight, he screamed ‘I'm gonna whoop your ass’ before the bell even rang.