Da steppt der Bär.

“The bear is doing the step dance there.”

It's going to be a great party.

Zwei Fliegen mit einer Klappe schlagen.

“To hit two flies with one flap.”

To kill two birds with one stone.

Da liegt der Hund begraben.

“There the dog is buried.”

That's the crux of the matter. That's the real issue.