was that joker's dad at the beginnig?

It was the Joker himself after a failed stand-up comedy gig.

I think you'd enjoy the graphic novel Batman: The Killing Joke.

That was The joker before he became "The Joker."

I agree with the other user, you should definitely read "The Killing Joke." It tells most of The Jokers back story. Most of it has already been mentioned: Failed Comedian with a pregnant Wife, His first attempt at becoming "The Red Hood," His accident that gave him the Pale skin, Green Hair and crazy Grin, etc. Most of it has already been explained in the film but I figure you should still read the Graphic Novel because...it's damn good.

Some people count sheep. Doesn't work with AlwaysCool, just gets him excited.