Hi thought i would start off with something small to start my arrival at the forums
...I've already searched and i'm surprised this method hasn't be posted before.
WHAT YOU NEED
5-10 Full & Unused Match-boxes
Large Real of Sticky tape or any medium width tape
HOW
1. Take the cover of the box off the container which hold the matches them selfs.
2. Rip off one of the sides which has the film of red paper which you use to light the match with. Keep the left over paper!
3.With the ripped off red paper Tear off each end about 1cm in so it can fit in the end of the matchbox.
4.Slowly place it inbetween the heads of the matches and the box of matches.BE CAREFUL NOT TO LIGHT THEM . Otherwise you may get a nifty burn.
5. With the left over paper from Step 2 put it back around the matchbox, as if one side was never gone.
6.Tape the whole Box so it becomes air tight (2-3 times verticly and horizontaly then fold the extra flaps of tape)
7. Throw at a hard surface , WALA ALL DONE 
NOTE
Even though it may sound lengthy to make it is quite quick. A minute per box.
Harmless compared to other explosives they are great fun to use whilst riding past people on the street for a quick scare :P
Thanks for reading this is my first tutorial here 