Adam Lowe has a great writeup on setting up Vim for Ruby/Rails work.  It’s a pretty great solution, using pathogen.vim and the git repos for the bundles, but he didn’t mention how to update your bundles in an easy manner…

$ find . -name ".git"  -type d -prune -execdir git pull \;

This is a little command line snippet that will search for git repositories in all of the subdirectories of wherever you run it and update them.  Really handy in this case, because you can update all of your bundles at once, but it will work in any case where you have cloned a bunch of repos and want them to all stay up to date.