The easy one
Fossil scm
Fossil is a simple revision control software written in C89. It uses SQLite as a database. This lightweight softare is a simpler alternative to git with a built-in bug tracking, wiki and forum.
Running from a single binary, it also can be compiled as a statically linked binary which is helpful for a chrooted setup like a OpenBSD server.
Basic Commands
$ mkdir repo && cd repo
$ fossil init repo.fossil
$ mkdir workdir && cd workdir
$ fossil open ../repo.fossil