Mercurial aka hg
Everybody writes his own SCM these days.
Here's 'yet another' one: mercurial, which is also called hg, the chemical symbol for mercury.
In the first glance it's quite like git. But it's more lite-weight, of less sized repo, with http builtin, full pull/merge/push support, etc. And it's written in python, which results in small codebase.
Read this doc for basic usage (feels home if you're familiar with other SCM tools anyway).
I'm now using it to follow Linus' tree and the mercurial itself. Works fine. Not bad. =)
