I did a whole 2 month project on high speed photography (for my Final Major Project at College a few weeks ago and won the Fine Art Photography Award

starting with using a manual flash to freeze water droplets but this only works in a dark environment as using flash in daylight the daylight overpowers the flash leaving blurs etc. I then discovered I could just use this tank for several shots with a high shutter speed but it wouldn't have worked say if I'd of put a black piece of card behind becasue there wouldn't be enough light.
If you want to try this get a cup fill it 3/4 up with water then get an assistant to drop something anything into the coin having pre-focuses the camera on a tripod with a high shutter speed and get used to manualy clicking the shutter at what you think is the right time. It's a bit hit and miss but it gives some amazing results.
There's a few more from this series on mywebsite under misc.