The Midwest Marching website offers up to date information on available competitions as well as results and judging information from previous competitions. Additionally, there are great resources in the articles section.
This is the music theory fundamentals placement practice exam for Fredonia school of music. It is a great resource for upperclassmen that are considering majoring in music in college.
The Radio Arts Foundation of St. Louis Classical music website offers live stream of their music. It is great to turn on during any down time in the class room.
This website provides many flash card music theory quizzes that can be projected on a white board. It has topics ranging all the way from note identification to inverted chords with roman numerals.
This website is a great resource for music theory lessons. Works well on white board but even better with a smart board and involving student interaction. Starts with the staff and goes all the way through analysis.