How do I force iCal to sync?

I've recently set up my Google Calendars to hook into iCal on OS X Lion. I've noticed though that when I make a change in iCal, it doesn't sync instantly to Google Calendar. I'm sure that iCal will eventually sync when it gets a chance, but because I don't leave iCal open all day, I'd like the ability to force it to sync before I shut down. Is this possible?