How do I remove ghost Calendar events?

My iPod Touch 3rd Generation is synched to a MacMini. Both devices have the latest version of iCal.

Last year (2011), I tracked my work schedule, including commuting time & method. For example, I met my vanpool at 0400 every day. Thus, I had daily events reflecting my work & commuting schedules.

Presently, I continue to track work & commuting events. The MacMini iCal application simply shows the correct schedule events.

However, the iPod Touch shows the current events PLUS the previous events, e.g., vanpool commitments, overlayed (there's a 30 minute starting differential; this is how I've recognized the difficulty).

Why don't the ghost events appear on the MacMini iCal?

How do I eliminate the ghost calendar events from the iTouch?

Thanks!