Google Docs supports .odt just fine; it's just Google Spreadsheets that's broken for .ods.  It worries me when proprietary services lose support for free formats... (Though it doesn't look like this lossage is intentional, obviously: they're still offering .ods in the "Download As" menu, which presumably means they expect it to work!  If I were being more constructive, I'd find the appropriate place to file a bug report, but it's always hard to motivate myself to file bug reports against non-free code, even non-free code that I have to use sometimes to communicate with my clients.)