I bet a friend that a semi-competent dev. could write a basic Facebook clone in C in a couple of days. To make things a bit more interesting I decided not to use anything other than the standard GNU C lib and SQLite3. This is the result.
This will not work on Windows and it's only been tested on OS X Mavericks.
git clone https://github.com/Bogdanp/facebooc.git
cd facebooc
make run
This is just a fun exercise. You wouldn't want to use any of this code in a production env.