The beta for the new Steam Library is out today. If you want to opt in:

1. With Steam running, click on “Steam” in the upper left, then choose the “Settings” menu. (Preferences on Mac) or follow this link.
2. On the “Account” tab under “Beta Participation” click the “Change…” button.
3. Select the “Steam Beta Update” from the drop down list and click “OK”.
4. You will be prompted to restart Steam, please select the “Restart Steam” button.

I have to say I like what I see. Game pages are way more interesting now, and the dynamic collections are pretty neat. Collections are more or less the same as the old categories we had and you can use them in the same way if you want to, but dynamic collections automatically add games into the collection based on things like genre or tags. You can also do things like sort by hours played, Metacritic score, or size on disk. That is pretty nice if you are looking for something to play or trying to clear up some space on your hard drive. It looks like a lot of games need to get some updated artwork for the new interface though. I am sure a lot of the older games will never get updated, which is unfortunate.