Got multiple Google calendar accounts? Wish they would they all show your actual availability regardless of which account has a scheduled event?
This Google Apps script looks at calendars in your other Google accounts and puts blocks in your current account's calendar where your other accounts have events.
Additionally, this script removes blocks from your current account's calendar when your other calendars no longer have events.
Now your current calendar always shows your availability, taking into account all of the events in your other calendars.
If you share all of your Google accounts' calendars with each other, then you can install this script in all of your Google accounts and they will all stay in sync. (When any two accounts are looking at each other, at least one must be able to see the full event details of the other, not just "busy" events, for the automatic removal of blocks to work.)