Playing trombone is SO FUN!! The best part about it is how the slide works. When you blow into the trombone and keep the same tune,you move the slide, and the tempo changes!! I think it's cool because you're keeping the same tempo, but when you move the slide, the tempo completely changes ( well, not completely changes, but it still changes) !
By Josef Plch (Own work) [Public domain], via Wikimedia Commons