Normally iCal has only the ability to open one window, this is usually fine for most normal use. But every so often you may want a second window to spice things up, or to help you with your day to day iCal eventing. To this little trick is simple. It only involves my favourite thing on a Mac, the Terminal command line.
Open up Terminal and copy and paste the following. This will set a small debug menu item into your menu where a magic shortcut will appear.
defaults write com.apple.iCal IncludeDebugMenu 1
Once as you have hit enter restart iCal or open it up. You should then have a debug meny next to help. Within the menu there should be an option which says “New Calendar Window”. When you hit that button a second window will pop open.
Both windows will be kept sync’d up, which is another bonus feature. If you want to remove the little hack type the previous command again but replace the “1” with a “0” and you are all set.