My girl was in the hospital April 1 and we amused ourselves by thinking of ways to goof on the staff. We laughed about calling code blues, turning off the electricity to ICU units, attaching her little finger clippy thing to a dead body so it would send the staff running in to resuscitate her. We thought up fake symptoms to tell doctors.
We joked about cadavers (and parts thereof). Telling the families in the chapels that if only they had loved their dying people more, they'd probably be ok.
Setting off fire alarms. Shutting off all the elevators. Calling the police and saying there were gunmen in the ORs.
You can pass a good forty minutes giggling at stuff like that.
Don't think for a minute I don't recognize that a large part of the underlying nastiness of my mirth was a reaction to how afraid I have been. I'd have laughed at it all anyway, though.