Cool git commands (some shell in there too). Alias these to stuff in your shell if you want to use them quickly.

delete-merged-branches.sh

#deletes all branches that have been merged into master (except your current branch) (substitute "master" for whatever branch you want to clean against)
git branch --merged master | grep -v "\*" | xargs -n 1 git branch -d
#you can leave off the last command to just list them

fancy-git-prompt.sh

#Adds the current branch you're on to your prompt (put this in your .bashrc file)
#be sure to do `source ~/.bashrc` to load it into your current session
parse_git_branch() {
  git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
}

if [ "$color_prompt" = yes ]; then
 PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[01;31m\]$(parse_git_branch)\[\033[00m\]\$ '
else
 PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w$(parse_git_branch)\$ '
fi

list-recent-branches.sh

#Shows the branches you've most recently committed on, and how old they are (wow!) 
#(you can change out the arg to tail to show as many lines as you want, or remove the call to tail altogether)
git for-each-ref --sort=committerdate refs/heads/ --format='%(HEAD) %(color:yellow)%(refname:short)%(color:reset) - %(color:red)%(objectname:short)%(color:reset) - %(contents:subject) - %(authorname) (%(color:green)%(committerdate:relative)%(color:reset))' | tail -n 20