There's yet another interesting roundup of products hitting Humble Bundle's digital shelves tomorrow. The charitable gaming distributor announced on Thursday that it is rolling out a new monthly subscription bundle of online indie games. The subscription service will cost an even $12 each month (with 5 percent of that figure going towards charity) and unlocks on the first Friday of every month. These bundles will feature the company's standard curated mix of marquee and lesser-known gaming titles. To commemorate this new service, anybody that orders the bundle on Thursday October 1st, 2015 will receive a free copy of "Legend of Grimrock 2". Unfortunately, this new bundle is currently only available for Steam users on the PC.