Config files' backup.
I actually use ArchLinux + XFCE and Mac OS X. So... I only tested on that set up (and everything is working very well).
There's a bash script called backup.sh. It copies all folders and files in which is stored all my config (vim, tmux, zsh, emacs...) from home.
Config is set up with the set_config.sh script to the home dir of the other of my computers.