One year, my co-workers (I was still on orientation on a womens health floor) made up fake charts, filled the board, and told me we even had overflow of a male patient. They told me that he had severe dementia and had been wandering the halls all day. During report, they said they had been really busy and had not had time to get the I&O's for him and asked me to go get them. I went in and emptied the urinal of really nasty looking urine (applejuice and yogurt mixed I think) and threw away a nasty adult brief (dont remember what they used, but it was sicko!), and noticed that the bed looked funny.... I went over to see "him" and noticed that he had put pillows under the covers to make it appear as though he was in bed. I still had not caught on, and went out and told them that I had gotten the I&O, but that he was missing and had him paged overhead. They started laughing hysterically and told me it was april fool's.... I hadn't even remembered.
They were getting back at the night shift because my coworkers the night before had made them coffee, as they always did out of courtesy for the AM shift, and put in salt, sugar, tea, and many other things.... they always put creamer in their coffee anyway, and so when they went to drink it, just thought their creamer was bad.
Then there is the infamous KY jelly on the phone receivers, and telling them when they come in that they are way understaffed due to call in's and high census and noone to come in and help.