I realize this is an old thread, but now that I have OS2008 with Flash support, I went looking for a Flash-based stopwatch. I found a decent one at www.online-stopwatch.com. You can download the .swf file to your local filesystem and run it offline. Simply grab the .swf file and save it somewhere. Then open it with File Manager. It seems to use a little less CPU than the JavaScript-based stopwatches listed above, but it would still probably drain your battery pretty quickly.