Now that I am teaching High School, I still find the "weird instrument" day a fun tool to use in the class. By about 2/3's of the way through the course, the students are feeling pretty burned out from covering 1000 years of Western Musical History, so they get to decompress for a day while I bring in the more bizarre specimens of my collection. I give the students a chance to try a couple out (not the nose flute, though, for I dont think any of my students want to share my nose...), and in general, just try to open their eyes and ears a bit about the variety of instruments that the world musical traditions have produced.
It has occurred to me as I do these presentations, that the average student has such a limited experience when it comes to exposure to various sounds of instruments. The pop world is filled with the sounds of essentially 5-7 instruments, and unless a student goes out to involve themselves in more, that is about it. It is always fun for me to see an otherwise "jaded" high schooler, suddenly get very interested as I make a piece of PVC and a spring make thunder, or a clay pot sound like an entire drum kit.
Some may look on my weird instrument day as simply a "filler" class with little educational value, but I know otherwise. Sometimes it takes a little "weird" to bring the mundane back into focus.