Is there a way to copy or install another copy of the default theme? I really enjoy using it but I don't want to mod the default, I would prefer to have a 2nd copy of it to mod.
Well, to begin with, you're not encouraged to modify the default theme :)
1. Go to Admin>Configuration>Themes and Layout>Manage and install
2. Scroll down to Install a new theme>Create a copy of Default named
3. Give a name to your new theme
4. Click Install!
If you need to edit more than index.template.php and style.css, copy the theme file from the default theme folder to your new theme folder.
http://docs.simplemachines.org/index.php?topic=232
I'm going to mark this as solved as what guppy has said should cover what you want :). If this is not the case, please unmark the topic as solved, and then ask any further questions.
Thanks