Oh, I much prefer boomwackers! They are "cooperative" and don't go out of tune. They aren't expensive but are not cheap either. If your school is one a tight budget, you can google how to make them out of golf club holder tubes (is that what they are called, the long white or black tubes you put in a golf bag to keep the clubs from getting all beat up and tangled).
I personally love recorders -- but not when it's a bunch of elementary kids playing them. Ouch! I have six recorders and enjoy playing them and hearing others REALLY play them.