Open Road Media has a Sci-Fi Bundle currently on Groupees. Like HumbleBundle and StoryBundle, the premise is you pay what you want for the ebooks, with the option of donating some of the money to charity (10% in this case, to FirstBook). Act fast though, it ends in 7 days (so August 28th if I'm counting correctly).
For a minimum $1payment you get 6 books:
Snake Agent by Liz Williams
Moving Mars by Greg Bear
Refugee by Piers Anthony
The Blue Hawk by Peter Dickinson
Sunshine by Robin McKinley
Agent of Byzantium by Harry Turtledove
Pay $12 or more and get:
The Genome by Sergei Lukyanenko
Patton's Spaceship by John Barnes
Midshipman's Hope by David Feintuch
Dragonholder by Todd McCaffrey
Schismatrix Plus by Bruce Sterling
The Disfavored Hero by Jessica Salmonson
The Burning Land by Victoria Strauss
If the total purchases go up to $15000, everyone also gets Night Train to Rigel by Timothy Zahn.
There are some interesting books in this bundle. I've heard great things about Snake Agent and Sunshine. My only hesitation on buying it is the piles of unread books on my floor and shelves. But I like these bundles, I think they're a great way of getting older and/or lesser known books into readers hands.