Mozilla Labs together with IxDA and Johnny Holland presented the Summer 09 Design Challenge as part of their Concept Series. The challenge theme is "Reinventing Tabs in the Browser - How can we create, navigate and manage multiple web sites within the same browser instance?" Voting on concept submissions ends on July 5. Will take a while to make it through the over 120 concepts!

http://design-challenge.mozilla.com/summer09/showcase.php