If you have reason (e.g. troubleshooting) to review and/or edit site variables, you can do this via a GUI interface (rather than
drush vget/vset) using the devel module and then going to the following location on your site:
This will provide you with a clear list of all the variables and the ability to edit them via a simple text editor interface.
I found this easier (or at least more straight-forward) than using
drush vset, especially when editing arrays.