Edi Weitz's libraries are often brought up when people ask for exemplary code in Common Lisp, the kind to read and learn from. Are there any open-source Scheme projects or libraries that you can recommend above others?
I'm working in Gambit, so I'd prefer code without the Racket extensions. Applications in games or scientific/numeric computing would be a plus, but really I'm just looking for code to learn from. (Game and numerical code just tends to be easier to dive into for me, since the overall point of the project is readily understandable.)
Edit: I am looking for complete projects and libraries, rather than isolated snippets such as those in a book. (Partially this is because I'm already reading SICP, and I'm looking for real-world applied examples to complement it, rather than another source of isolated functions/macros.)