I would like to create a terminal based installer/wizard.
Ideally, it'd be like the Ubuntu server installer, or the Arch Linux installer - a ncurses (?) heavy GUI with lots of form and arrow key goodness.
Second best would be a simpler question/answer type thing, similar to the "adduser" command prompting for password, username, etc.
I am Ruby biased, and would prefer a scripting language (not C), but I'm open to anything. It will only run on Ubuntu server, if that helps.
What are my options?
InstallJammer can do what you want in the second form. No ncurses interface to speak of though. 0-] It's written in Tcl/Tk, so it meets your scripting requirement though obviously not in your language of choice. We all have our language of choice, I suppose. 0-]
It would be easier to answer if you specified what you're trying to do. If you're installing something, it might make sense to just create a debian package and use install time configuration options available via debhelper.
If bash or shell scripting is okay, I'd suggest looking at package "dialog". Just put "dialog" as pre-depends for your package and you can use dialog features for your deb installer.
Another possibility could be the "pdmenu" package (origin: http://kitenet.net/~joey/code/pdmenu/).
I'm not certain what you're asking. If you're looking for an implementation tool, you could look at urwid, which is a Python-based GUI toolkit library. It lets you write programs using GTK-style widgets and event interfaces for a text-based interface. If you're a decent scripter, it shouldn't be too hard to start from there and write the code to drive an installation process.