Development on Maxwell's Lemur was discontinuted at a young age, because Gnumeric is so much cooler.
Maxwell's Lemur was an attempt at a free (GPL) spreadsheet using Guile and Gtk. It borrows heavily from Siag. It uses a custom Gtk widget called an NGrid, written especially for this purpose.
This project is an inactive work in progress. Which is to say, it no longer serves any useful purpose, and I should really delete all this crap, except that I really like the spiffy title graphic at the top of the page.
Daniel Risacher <magnus@mit.edu> founded the project. Peter Norton <spacey@inch.com> is the lead developer. He has established a mailing list for developers at <spacey-lemur@ssr.com>. See the credits page for other people involved.
Despite the fact that the CVS repository is much more stable, there is still a pre-alpha release from 03 Dec 1997 can be downloaded by the brave or foolish in either gzip'ed or bzip2'd format. It won't install anywhere useful, but if it actually 'makes', the executable is in gui/lemur. I'm pretty sure it will work on a Linux box with gtk+971109, but on anything else I dunno. Let me know if it works (or doesn't work) on some other platform.
Obligatory Screen Shot: