http://blogs.discovermagazine.com/discoblog/2009/11/03/superhero-tip-protect-your-secret-lair-with-a-secret-knock-detector/ Quirky, funny, and surprising science news from the edge of the known universe. Wed, 25 Nov 2009 02:25:28 -0600 http://wordpress.org/?v=2.8.4 hourly 1