Don't know how many of you folks know of this, but there is an rpg version in the Humble Bundle type style...
Bundle of Holding
Mostly they tend to be rpg pdf bundles from the smaller, indie publishers, but they get the occasional wander into other things.
At present, they're doing the Scion stuff from White Wolf's Onyx Publishing.
They tend to do a "put x dollars in, and you get 2 or 3 books in pdf, but put y dollars in and qualify for these other 5 or so as well"