Last Updated Jun 10, 2009 1:26 PM EDT
Just enter a search term at the top of the page and this Bing/Google mashup shows both search engines on the same page, with a movable divider so you can get a better view of each side. You can use it for broad comparisons of search results, or drill into specific links and actually use it as a research tool.
If you want to, you can even interact with each search engine individually, but I think that kind of defeats the purpose of this very useful page. [via ghacks]