Nimble, Excel-Compatible Spreadsheets for *nix?

linguae writes "I'm running a FreeBSD desktop on a PC that has a 475MHz K6-2 processor with 64MB RAM. I use lightweight programs on my desktop such as Window Maker, AbiWord, and Firefox. I have been looking for a decent yet lightweight (and preferably Open Source) spreadsheet that is compatible with Excel, and also doesn't rely on dependencies such as GNOME or Java. I'm not an Excel power user, but sometimes I do have to share spreadsheets every now and then. I wonder if there is a spreadsheet equivalent of Abiword?"