The Humble Mobile Bundle 4 is available now and includes six Android games on a sliding payment scale.
Buyers can pay what they wish to receive DRM-free copies of Catan, Vector, Riptide GP2 and Zombie Gunship. Two additional titles, Badland Premium and Breach & Clear, are available by paying more than the current average (around $3.34 at the time of this post). Badland's in-app purchases are already unlocked at no extra cost.
Payments are split at the discretion of the buyer between the games' developers, charity organizations Electronic Frontier Foundation and Child's Play, and bundle organizers.
The Humble Mobile Bundle 4 will be available for 13 more days. More than 27,000 bundles have already been sold.