https://www.google.com/calendar/render?cid=hhlp4gcgvdmifq5lcbk7e27om4%40group.calendar.google.com

https://www.google.com/calendar/embed?src=hhlp4gcgvdmifq5lcbk7e27om4%40group.calendar.google.com

Parameters:

• mode=agenda
  Which mode to start in. Options are: day, agenda, ...
• date=20081101
  Show a specific day
• more