In the frenzy of the holidays, you may have missed Google’s little gift to you: they have subscribed you to the Google Birthdays calendar – whether you want it or not. Now you will be notified of every single birthday that every single person in your G+ circles has – whether you want it or not. Oh, and they have made it nearly impossible to figure out how to delete or unsubscribe from the Birthday calendar. So, here is how to unsubscribe from the Google Birthdays Calendar.

Wondering where did a Meetup group’s calendar go, and where the past meetups have gone? If you opted in to the new Meetup interface, you may find that you are no longer able to easily find the calendars and past meetups for the meetup groups to which you belong. We agree that the new site sucks! (If you haven’t already opted in to the new interface, count yourself lucky, and don’t do it!)

If you use Meetup.com as a way of finding fun and rewarding things to do, you may find yourself wondering how to sync your Meetup.com calendar with your iPhone or Android calendar, Google or Gmail calendar, Apple Mac calendar, Outlook calendar, or other calendar. Here is how to synch your Meetup calendar with your ics or other calendar.

If you have started receiving spam iCal calendar invitations on your iPad or iPhone or Mac, you’re not alone. This is because of some change that Apple has made allowing spammers to send you ‘in-app’ iCal invitations for calendar events. Here’s how to turn that off.

If you are using a Gmail calendar (actually a Google calendar), but are used to creating your calendar events on your computer rather than directly in the Google calendar interface, you may have gotten used to being able to create a “custom” repeating interval for your events (such as every X days or every other week, instead of every week or every month). Then, when you need to create an event with a custom repeat interval in the Google calendar interface, you may be perplexed at the seeming lack of the ability to create a custom interval. It’s actually easy to do, but like so many other things designed by Google’s engineers – and there’s the problem, they think like engineers, not like mere mortals – it isn’t obvious. Here’s how to do it.

Google has announced that, starting now, you can download all of your Gmail email, and also your calendar data. The Gmail download will put your messages in “mbox” format (a standard email format which most email programs can use, or at least from which they can import).

Do you use Google Calendar? If you answered “no”, well, are you sure that you don’t use Google Calendar? Because even if you don’t use Google Calendar directly, if you use a calendar on the iPhone, or on an Android phone, you may well be using Google Calendar on the back end without even thinking about it. The same is true if you “share” your calendar from your Mac. And here’s the thing, your calendar on Google may be set to “public” view by default. Meaning that anyone can read your calendar. And it will turn up in public Google search results.

Three researchers in Germany at the University of Ulm have discovered a massive security hole in Android – so big, in fact, that it affects at least 97%, and as many as 99%, of all Android users. The researchers, Bastian Könings, Jens Nickels, and Florian Schaub, have discovered that the security flaw allows anyone who is sniffing around your connection on an unsecured wireless network to acquire your Google authorization credentials from a specific token (the authToken), giving them access to your contacts, your calendar and, well – really any application that authenticates you by using your Google authorization credentials contained within that authToken.