A physicist got stranded at a hotel for a week when his laptop and passport were stolen. While he was waiting, he became inspired to completely rewrite everything that we know about gravity. He argues that gravity, rather than being the constant force that we assume that it is, could actually be an effect of something completely different. If this is true, than nearly everything that we thought that we knew about gravity could be wrong.  http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&pagewanted=1&ref=science

You can follow a link to his paper here