Vim Scripts

Tools

These projects work closely with the vim-scripts.org mirror:

vundle makes it easy to find and install plugins without ever leaving the Vim environment.
vim-update-bundles is a small Ruby script that reads your .vimrc to determine which plugins you want, then installs and removes plugins to match.
vimmer is a command-line utility and Ruby gem to install, update and remove Vim plugins.
Also see the alternatives below. They don't use the mirror but some of them make downloading scripts much easier.

These projects help manage the plugins once they're downloaded:

Pathogen and its lightweight alternative Unbundle allow you to store your scripts individually in ~/.vim/bundle/ instead of one gigantic communal directory tree.
tplugin can be thought of as a mix of Pathogen and AsNeeded.

Less software is more. If you want to manage your plugins by hand, here are some docs.

A screencast showing how to manage plugins manually using Pathogen and git submodules.
The Modern Vim Config with Pathogen, a blog post by Tammer Saleh.

These perform their own package management instead of using the vim-scripts.org mirror.

vim-addon-manager is a package manager written 100% in VimL.
Janus is a collection of plugins but does include its own plugin manager.
Vimpire reads bundle tags from .vimrc and updates plugins to match. Written in Python, supports Mercurial.
Vimana is a Perl-based package manager.
jolt Vim Package Management written in python
vim-nicktears manages Vim plugins using Rubygems.
Vim Script Updater manages plugins using Python.
GetLatestVimScripts is a 100% VimL solution.