Speaking of homemade kazoos -- I could never get much of a sound from a comb and tissue paper (maybe I had trouble holding the paper taught enogh), but I've had great success with the "toilet paper tube" kazoo:

items needed:

empty toilet paper tube
Waxed or greaseproof paper
scissors to cut the paper
a strong rubber band.

Cut a circle from the waxed paper that's a couple of inches wider in diameter that the diameter of the end of the toilet paper tube. Fit it over the end of the cardboard tube, and hold it tightly in place with the rubber band (will probably have to put at least one twist in the band, so it can go around the tube a couple of times).

Decorate at will.

Hold the finished kazoo tight against your mouth (obviously, you're not going to put your lips around it), and hum, sing or speak into it.

Reduce, reuse, and recycle!