Same here with spocalc.xls, but I did find a version called spocalc.sxc that does work in OpenOffice. I don't recall where I found it, though.
Edit: I found it. It is at Mike Sherman's site.
http://home.earthlink.net/~mike.sherman/bike.html
For some reason, I only get the version for 2.1 to work, the version for 3 has the buttons, but they don't seem to do anything for me, yet.