There's a new Humble Bundle available for those looking to expand their Steam libraries this week.
The "Endless RPG" bundle features games with long average play times and for a dollar or more you'll get Borderlands (Game of the Year Edition), The Incredible Adventures of Van Helsing (Final Cut), and Wurm Unlimited. Pay more than the average (currently around $5) and you'll also get Endless Legend (Classic Edition), Borderlands 2 (plus DLCs), and Guild of Dungeoneering. Pay more than $10 and you also unlock Borderlands: The Pre-Sequel.
If you've got plenty of time on your hands you may want to look into it.