Help grow this list! Here's a jQuery plugin to add the Konami code to your site in one line: http://www.gethifi.com/blog/konami-code-jquery-plugin-pointl...
I think things like this are the ones that make technology fun.
I was looking to add eastern eggs to my site, so I got these two links that show interesting eastern eggs for ideas:
http://www.compukiss.com/tech-talk/easter-eggs-high-tech-sty...
http://www.telegraph.co.uk/technology/google/6201814/Google-...