Helium
Helium is a floating browser window that allows you to watch media while you work. Your content will never fall behind your other windows even as you switch tasks. Helium supports a customizable translucency mode that allows you to simultaneously see your content and your work. Even cooler, Helium does not intercept mouse clicks when it is translucent! That's right, you can still click, drag, scroll, even flick behind your floating content. When you want to interact with the browser again, just click the icon in the dock and you're back in control.
