Recently I saw this site , which claims to be working offline, in fact it does but it sucks because it was built using Flash.
Now since we have HTML5 browsers ready!!, we can have 100% working offline website.
On Feb 11 2012, it was Bar Camp (11th) in Bangalore so I decided to educate people about offline capability of HTML5. BCB11 was really nice and many talks were awesome including a talk from Sameer Panchangam on hypnotism.
Here is Presentation from my talk.