Admittedly, I'm a total geek for the "old classics", but I find this website absolutely amazing! In about 3 minutes time I was able to locate about a half dozen pieces that I've been looking for at some point or another since I started teaching. I think there are resources that every band director could use here.
Video game-like simulation through various lessons for individual instruments. I see this being effective for beginning band/orchestra and possibly further applications within MS band.
Excellent tool for percussionists to HEAR what the 40 essential rudiments are supposed to sound like and gives a very good methodology for practicing them slowly and gradually improving. The one downside (and it is significant in my philosophy) is that many of the illustrations use traditional grip, whereas I teach only match grip.
Seems like a fun website to have students play for 'fun'. Caution, some of the fingerings in the graphic are incorrect, although students can click on any pitch and be given the correct fingering.