Me and a friend spent the day last sunday trying to make somthing "musical" out of the junk sitting on my drive and this the best of the results. We inserted a small copper pipe (about 20cm, 1" diamiter) into the top of a traffic cone and played it in the same fashion you would a cornet for all the neibourhood to hear.
Step 1: Adopt a Traffic Cone.
Other Materials: A piece of copper pipe roughly an inch in diameter (or something similar), Gaffa tape/Duct tape, scrap of cardboard (optional).
Step 2: Removing the Weighted Bottom of the Cone.
Bellow is a picture of the cone with it's weight attached incase you didn't understand what I meant.
Step 3: Attaching the Mouthpeice.
Duct tape over the top of the traffic cone so there is no hole. Then proceed to slice a slit into the tape into which insert the pipe. Test how far into the cone the pipe makes the clearest toot. Tape around the pipe and cone to secure. You can add scraps of card as you tape for stability of the pipe.
Step 4: Playing.
I'll add a video or better description later if requested :)
Ours is decorated with spraypaint but I belive it looked better beforehand.
Please comment with any recomendations/improvments.