Turn an old plastic bottle into a 50W lightbulb

Fill a plastic bottle with water, add a small amount of bleach to keep it clean, stick a film canister over the cap to stop it corroding in the UV, stick it in your roof, and hey presto an everlasting prismatic 50W lightbulb!

httpv://www.youtube.com/watch?v=_zMAWztZ6TI

via http://www.inhabitat.com/2010/04/02/sundolier-robot-pumps-sunlight-indoors-for-powerful-daylighting/ and Slashdot