Try Google Zeitgeist, which lists the most rapidly growing and most rapidly declining searches over a week’s period.
Country-by-country favorite searches (not rates of change) are given as well. In Russia the most popular query in October was "pet therapy." In the Netherlands it was "Britney Spears." In Germany it was "telefonbuch". In France it was…er…"France".
Here are some fun graphs of search patterns, along with year-end results from 2003.
Thanks to Kyle Cooney for the pointer.