Writing jokes

I think all profession jokes are lame, but these got a chuckle out of me.

How many mystery writers does it take to screw in a light bulb?

Two. One to screw it almost all the way in, and the other to give it a surprising twist at the end.

How many screenwriters does it take to screw in a light bulb?

Why does it have to be changed?

How many cover blurb writers does it take to screw in a light bulb?

A VAST AND TEEMING HORDE STRETCHING FROM SEA TO SHINING SEA!!!!