It's the bottom bracket spinney thing! There's a crack running down by the axel
The spinny thing is a http://en.wikipedia.org/wiki/Bottom_bracket which fits inside the frame. If it were broken, you could replace it and keep riding your bicycle. I'm still not sure whether you mean that or the frame, the BB shell. If it is the latter, you shouldn't still be riding that. If you keep riding it, the frame will break, causing you injury or death.
The spinny thing is a http://en.wikipedia.org/wiki/Bottom_bracket which fits inside the frame. If it were broken, you could replace it and keep riding your bicycle. I'm still not sure whether you mean that or the frame, the BB shell. If it is the latter, you shouldn't still be riding that. If you keep riding it, the frame will break, causing you injury or death.