Using the Insert >> Calendar method the embedded cal will always show the events on or near the current date. However sometimes you might want the events shown to start at a particular date. This might be useful for a conference website and the session schedule.
To do this you should use the Embed Gadget under Insert >> More gadgets.
You will need the embed code for your calendar from Google Calendar.
Go to Calendar Settings and click on the HTML link. Use the configuration tool to set the calendar as you wish.
Here's the trick. Look at the code and find the timezone setting. It will start with "ctz". Just after this add "&dates=YYYYMMDD/YYYYMMDD". These are the first two dates (consecutive) that you want displayed.
<iframe src="https://www.google.com/calendar/embed?showDate=0&showTabs=0&showCalendars=0&showTz=0&mode=AGENDA&height=600
&wkst=1&bgcolor=%23FFFFFF&src=qanl0udn6g5phaq2grcnldoe2s%40group.calendar.google.
com&color=%235229A3&ctz=Asia%2FSingapore&dates=20130401/20130402" style=" border-width:0 " width="800" height="600" frameborder="0" scrolling="no"></iframe>
Now copy this code and paste it into the Embed Gadget on your site. Bazinga! The calendar now starts on the date you want.