Multitask with ease. 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.
Aurora is a floating browser to keep you entertained and productive.
FloatPlayer is a simple Mac app that plays a floating YouTube-video on your screen. The player is visible even on top of full-screen apps.
It's also completely open source.
Check it out on GitHub.