Q: How many Zen masters does it take to screw in a lightbulb?

A: <smash the lightbulb>

OK, try again.

Q: How many Zen masters does it take to screw in a lightbulb?

A: Five. Two to argue over whether the buddha nature already resides
in the empty socket, one to light a candle instead, and two to
shovel out the outhouses.

On a related topic:

Q: How many psychoanalysts does it take to screw in a lightbulb?

A: How many do you think it takes?

Tom Neff