I came up with a pretty nice logo/favicon () for Git, to be used on my gitweb page. That's the plus-minus sign, if you didn't notice. Jesse pointed out that the "G" looks like a reload arrow, which wasn't intentional, but I like it.
The default logo and favicon for Git/gitweb are and .
The font is Helvetica. TIFFs: Git logo.tif and Git favicon.tif. Free to modify and redistribute with due credit, and obviously free to use.