One for the Ladies!
OK, so I've got absolutely no personal experience of this one, and never will have, but three women I know swear by the 'mooncup' as an alternative to disposable sanitary towels and tampons. None of these women are ardent eco-warrior/tree hugging types, rather they find the cup much more practical. You simply insert it, go rollerblading/windsurfing etc (as menstruating women do according to Bodyform), remove it, wash it and repeat until done when you put it away til next month. At £18.99 the manufacturer claims it will pay for itself in 6 months and will last for several years.
Before you ask, I haven't seen a detailed life cycle assessment of this product verses the hundreds of disposables it will replace, but I would expect it to be many times better by any measure you care to choose.