Utils...
Algorithms...
Convert hex dumps to binary blobs hextobin.
Linux Kernel...
popen() like call that handles stdin/stdout/stderr: popenRWE().
A simple C implementation of a min-heap.
Generating primes, which won for speed at an OCLUG contest in 2001.
Pretty tracing: pretty-function-tracer.c [html]
Entropy injector: entropy-injector. [blog entry]
A simple in-kernel server thread: kserv.
Macros that write data to /proc nodes over multple iterations: proc_output.