For example, as a health lawyer focusing a part of my practice on HIPAA privacy and security compliance issues -- I found the search for the term "HIPAA" interesting. Relatively flat line on the volume chart -- going down a bit from 2004 to 2005 and a little rise in the beginning of 2006. Interestingly enough the top city for the search was Nashville. I suspect this is largely due to the fact that a number of national hospital companies are based in the Nashville area.
Give it a try and post your creative legal uses for Google Trends in the comments.