This may not be the reason slow motion cameras were invented (or maybe it is, what do I know?), but this highlight reel from a Danish TV show is just a lot of fun to watch. Do yourself a favor and watch it in HD.
It features such clips as "Birthday Cake + Fireworks", "Coke + Chainsaw", and "Wrecking Ball + Cabbage". The indoor fireworks are a personal favorite of mine. It's a long video, but well worth the time.