Apple’s iCal has the ability to use timezone-aware scheduling. This comes in handy because I sync it with my Treo, which changes time zones automatically. Unfortunately, sometimes it’s easy to forget which time zone you’re looking at, and become confused.
Yesterday I accidentally discovered that if you change your date/time format preferences to include time zone (even for the “short” format) in System Preferences, the time zone will be included in iCal events as well: