You want obscure?
Go to the Gutenberg Project and browse the Sci-Fi and Fantasy shelves.
Good selection of public domain stuff available in all e-book and html formats. Some terrific short stories and Novels. Also first issues of Amazing stories. Good but brief section of early works of Harry Harrison and others.
FREE E-BOOKS
Link to Gutenberg Project Science Fiction shelf. There is also a Fantasy shelf. Check out the new additions for the occasional pleasant surprise.
http://www.gutenberg.org/wiki/Science_Fiction_%28Bookshelf%29