Why hasn’t anyone thought of this before? A radio which connects to your shower and is powered by the water passing through it. The only problem could be if it slows down the flow of water, but apart from that it’s an ingenious idea.
You can see who sells it at www.google.co.uk/products or read more about it and it’s inventor on the guardian site: www.guardian.co.uk and see other products from the same firm here: www.tangogroup.net