If someone using the iCal Events 2.2 Dashboard widget wants to keep all present day's entries, even if their time has already expired, it's easily done.
Here's how:
defaults write ~/Library/Preferences/widget-com.benkazez.widget.icalevents \
showAllCurrentDayEvents -bool YES Mac OS X Hints
http://hints.macworld.com/article.php?story=20060123160949127