Bundle of Holding puts together packages of role playing game ebooks on a pay what you want basis (minimum $4). If you pay higher than the current average you get bonus books as well. 10% of your payment goes to charitable causes. All books are completely DRM free.
Right now they are offering a Bundle of GUMSHOE that includes the following rpgs from Pelgrane Press, Ashen Stars, Mutant City Blues and Night's Black Agents and other support materials. There is also the possibility of adding more books later on, which you will receive regardless of when you purchase during the offer period. This bundle is only available until September 28th.