Go to the last level on Dark Carnival get a propane or pipe bomb.

There should be two towers, go to the tallest one and set the propane right next the edge that does not have railing until it moves a little but does not fall off.

Now look at the ladde,r then look to just to the left of the ladder and look up a little.

You should be looking at the roof over the stage.

Now press RB and in front of you should be the propane.

Shoot it and start pressing Y rapidly and then keep pressing it and you should land on the stage roof.