Launch a one-off git server from any local repository.
I [tweeted this already] but I thought it could use some expansion:
Enable decentralized git workflow: git config alias.serve "daemon --verbose --export-all --base-path=.git --reuseaddr --strict-paths .git/"
Say you use a git workflow that involves working with a core "official" repository that you pull and push your changes from and into. I'm sure many companies do this, as do many users of git hosting services like Github.
Say that server, or Github, goes down for a bit.