BidBuddy lets the world see your bids:
BidBuddy, an Adwords bid management tool created by The Search Works leaks valuable Adwords data, such as CPC through its cookies. The bid management tool redirects visitors through the domain tsw0.com where it sets a cookie with the Adwords data.
Sorta makes you wonder about the value and sophistication of other third party bid management tools, eh? A small sample of other keywords and bid prices located here.
Hat tip to Martjin.