Hello to all and thank you in advance if you can help me.
I am about to try to repair a 2 foot crack in my drywall ceiling. It was caused by someone( OK me) stepping on it from the attic. There is no hole or actual gap but the drywall was displaced slightly(has a bulge and has an incomplete crack). It is located roughly 1/2 way between the studs. It looks about like what I think drywall would look like if you bent it until it just started to crack. Any suggestions would be appreciated.

see if you can push the section back up if its between 2 joists. If you can, add a 2x4 between the joist in the attic above the cracked area, then screw the cracked area to the 2x, hit it w/ some compound, (may need 2 coats) sand then paint.

I would run a board the length of the crack and screws about ever 6'' on each side. A wider one by may be better than a 2x4. The screws will pull the drywall up flat against the board.

Another option I saw recently that may help is to:

Cut a section of plywood/osb at least 6"wider than the crack (or as wide as the joist spacing will allow) and as long as needed.

Attach 2 trimmers to the bottom of the plywood along the outside edges so that it is thicker on the edges than the center. The trimmers can even be another section of the plywood.

Put the new support board, timmer side down (Think of an upside down U).

Screw the drywall into the support board. This will bring the ceiling as the support board acts as kind of a spring. Just be careful to not bring it up too much. Then, just finish as the other guys suggested.

I saw this in a homeimprovement magazine where they were showing how to minimize butt joints in drywall. If I can find the article on the web, I will post it.