Hippo water savers
I got one of these when we moved into our new house and had our first water bill. I have often wondered where they came from now I know!
You can buy them off this page, £6.99 for three including VAT and P&P. Although I don’y know many people who have three toilets. They might make good presents for people who live in drought affected areas though.
If you are concerned about saving water visit beat the drought - a lot of the ideas mentioned on the site should be pretty much common sense to most people by now or I would hope so anyway!
Slightly more fun way to get a hippo perhaps:
http://hippo.antiapathy.org/