A game may be non-rentable for one of several reasons:

•The title may be rare or out of print, and there may be limited or no copies available for GameFly to purchase.
•The title may be a future release and may become available to rent.
•The title may only be sold with and/or be playable with a peripheral that they cannot send to you in their mailers.
In all three instances, they keep these titles on the Web site so you can still access the content that is available, even if the title is non-rentable and cannot be added to your GameQ.