okmij.org
A whole handfull of Scheme programs and applications, including Treaps ("A sorted dictionary data structure based on randomized search trees."), Scheme database interfaces, parsing utilities for CGI and XML, binary I/O and applications, POSIX interfaces, a purely functional OO system, and read-time application.
URLs from okmij.org:
URL:
http://okmij.org/ftp/Computation/
URL:
http://okmij.org/ftp/Scheme/macros.html#Macro-CPS-programming
URL:
http://okmij.org/ftp/cpp-digest/Functional-Cpp.html
URL:
http://okmij.org/ftp/Scheme/index.html
URL:
http://okmij.org/ftp/
URL:
http://okmij.org/ftp/README.html
URL:
http://okmij.org/ftp/Streams.html