If you use Outlook's calendar for your personal calendar, but Google Calendar for a work calendar or group calendar with others, you're in trouble. You need to check both calendars regularly, and you'll have to copy events back and forth between them--a very time-consuming task, and one that's very prone to error.
This little utility solves the problem. It synchronizes your Google and Outlook calendars, and offers many options for synchronizing the two. You can fully synchronize both in both directions, or only synchronize your Google calendar to your Outlook calendar, or only synchronize your Outlook calendar to Google. There are other options as well, including selecting how many days, weeks or months of your calendar to synchronize.
The free version of SyncMyCal won't perform synchronizations automatically; you'll have to tell the program to do it manually. And if you want to synchronize more than seven days of your calendar, you'll have to use the for-pay version as well.
Note: This link takes you to the vendor's site, where you can download the version that's appropriate to your system. The vendor requires you to accept its terms and conditions before downloading.