Nick Farina - Git Is Simpler Than You Think. Really nice tutorial and view of some of the innards of git, and how to understand the mechanics behind it to get around better.
Did you know the top result for "git tutorial" is this manpage on kernel.org? I will give you a gold star if you can read the whole thing without falling asleep.
So instead let's pull over, open the hood up, and poke around.