Vim-addon-install is a project mainly written in ..., it's free.
A script to fetch and install vim addons from the command line given the name.
This is a short script I wrote to automate the installation of vim addons from the vim.org website. Use it as follows: ./vim-addon-install.sh $PLUGIN_NAME to install the plugin $PLUGIN_NAME.
This script definitely works with .vim files, and works with tar.gz and .zip files that are created such that they can be unpacked in the .vim directory. If the .vim file is specified as a color scheme on vim.org, then it is automatically installed to the colors folder.
This script is still experimental, so use with discretion.