At our Christmas staff party in mid-December, one of my co-workers brought a niftily-presented snackie tray. It had different kinds of cheese on it, and one mound was encrusted with almonds (it was supposed to look like a pine cone). With them, and some grapes, were a couple of sprigs from a pine tree, long needles, green cones, and all. We all joked that it would be funny if one of us pretended to choke on a needle or something. While we didn't do that, I got the idea that since this person deals with health and safety in our workplace, I'd make up a joke letter for them. I got a legit logo, legit contact info, legit name, legit terms... oh, it was all legit. Well, except for the lying part of it. I got our secretary to sign it, and I faxed it upstairs from downstairs. Our secretary delivered it, and it worked marvellously. It was read with shock as the colour went from their face. "Oh my God... did you see this? Oh my God..."
We'd say ( the staff knew it was coming), "Oh... no, what is it?"
It was only a minute or two of shock, but it was great... and a good chuckle was had by all, including the one that was had. Mwah ha ha ha haaaa...