When Did I Start Work Today (linux)

When working in Windows (XP at least) it's an easy matter to jump to the event viewer security log to see when you first authenticated this morning. Here's a handy way to get the same information from Linux. Just replace the [your.user.name.here] with the name with which you authenticate.

su -
grep pam.*[your.user.name.here] /var/log/messages