Using Dropbox to Share Git Repositories
First, create a Git subfolder inside your Dropbox folder. Then you can share the individual projects inside that folder with whomever you want (or just use it for instant offsite backups).
From inside a Git project:
git clone --bare . ~/Dropbox/Git/gitproject.git git remote add dropbox ~/Dropbox/Git/gitproject.git
When you're ready to push: