Unexpected Uses of Control Key

1. Open a folder in a new window (or not)

If you are not setting your "Finder Preferences" to "Always Open Folders In A New Window", command key + double click can always reverse your default setting. You can also press "Command-Control-O" to open a new window with your current directory.

2. Open a new window for the enclosing folder

When you are looking at the contents of a folder in the Finder, pressing "Command-Up Arrow" opens its enclosing folder.

3. Get a summary of info with multiple files or folders

Selecting multiple files and then "right click " or "command-I", it shows you the information of the files  with several windows. But with "Control", it shows you the information with a single windows. 

-- "right click" + Control

or

Command-Control-I

Set Default Calendar on iPhone, iPod touch, iPad

To set a default calendar on iPhone, iPod touch, and iPad, do the following:

1. Press Settings > Mail, Contacts, Calendars.
2. Go to the section labeled Calendars.
3. Press Default Calendar.
• If you do not see Default Calendar in the Calendars section, then your device has only one calendar.
4. Select the calendar you want to set as the default calendar for your device.
5. Press Mail... at the top of the screen to return to the previous page.