Do you have a google account of some description?

Google are moving towards a targeted search, if you're logged into google (gmail or another of their many programs) whereby results are sorted and prioritised based on that user and their history/location etc... It could be that your search is picking up results based on your preferences which would obviously be badminton.

I read about this in an Australian Business magazine -- ".net"

I am unsure how much truth there was in the article but there were statements from Google execs..

Have you tried to searching through a proxy to see if the order changes?