Really good job on this. One feature that you might want to think about is adding support for timezones. I live in Europe so I have to re-calculate all times in my head. It would be nice to have an option to set a specific timezone.
An idea would be to integrate this with a DVCS system like Github och Bitbucket. Jetstrap could do commit/push at a frequent interval, thus allowing you to revert your changes. Good job.