An artist developed a shower curtain that literally kicks people out of the shower after four minutes. According to AOL News, the creation has soft spikes that inflate after four minutes of the water running which forces the person in the shower to get out.
This invention is not to buy (yet?), but it does serve as a reminder for us that personally conserving water can be as easy as shortening shower time.
For conservation ideas, visit Drinktap's conservation page.