This device in a Japanese toilet makes the sound of running water, to mask other, ummmm…, indelicate noises. Saves water, since patrons don’t feel compelled to flush a toilet multiple times to block sounds.
[youtube=http://www.youtube.com/watch?v=ond_IaNA4wk] video link
[kudos boingboing]
Previously: When Ambient Sounds Go Bad, Celebration of Nature Sounds