According to this announcement on Steam Community, Valve’s game Portal 2 Beta is now available on Steam for Linux. To access it in Linux, you will need to opt in to the beta from the Portal 2 properties in the Steam Library.
WebUpd8 reader Martin Kozub has created an Ubuntu-like skin for the new Linux Steam client which includes the Ubuntu font, default Ubuntu colors and window buttons (Ambiance), thin scrollbars as well as Ubuntu (Humanity) back and forward icons.
Steam for Linux beta has been released today and for now is only available to 1000 lucky users who have applied using the Steam beta survey. But there's a way to run Steam for Linux even if you didn't receive an invitation. Read on!