Many people have several Gmail accounts.  A typical setup is one personal account and one or two professional ones.  One great feature, a path blazed by Plaxo, is the ability to synchronize Gcals across accounts.   But this is the catch, and it’s important:  you may refer to one as your main calendar, but reminders to your computer or phone must be enabled on each calendar.   The hole is a tiny one, but worth noting.