I'm game

Geeky, white guy speak. Probably came from the racquetball courts of a local YMCA.

"Hey, Todd. Wanna grab a cold brewski after work today?"
"I'm game."
"Alright, bro."

I'm game

Yea i'm in.
or sure I'll do that.

>let's go eat.
>I'm game.

I'm game

As in I'm likely to do that, might be fun; often references challenges to keep up in drinking games.

"Hey, let's do Irish Car Bombs!" "Sure, I'm game."