iCal has been completely overhauled in OS X Lion - here are 8 tips to help you take advantage of all the new features.

Create a quick event

iCal now has a a great new way to add events that means you no longer have to spend ages filling out dates and times with fiddly controls. Instead, just click the + button in the toolbar or press Command-N to bring up the Quick Event popover. This allows you to type in the event details in a human-readable form — for example, “Movie at 7pm on Friday” or “Meeting at 3pm until 6pm” — and iCal will interpret what you mean and create an event.

Specify times in the event name

When creating events by double-clicking a day in month view, the new default behaviour is to create all-day events. If you want to create a normal event, just specify the time when typing in the event name. iCal seems to be quite flexible at interpreting what you mean - things like “Gym at 6” and “4pm Meeting” will both work.

You can also specify the length of all-day events in this way. Just type “Holiday until Saturday” or “Jim away until the 14th”.

Remove the leather effect

The new look and feel of iCal was one of the most controversial changes when Lion first came out, provoking outrage amongst many UI purists. If the new look isn’t for you, there are a couple of simple tweaks that will change things back to normal. First, if you just want to remove the torn page effect from the bottom of the toolbar, the Big Bucket Development blog shows you how to achieve this by replacing a single image. Alternatively, if you want to get rid of the new look completely, MacNix has a simple method that can bring back the aluminium look in both iCal and Address Book.

It’s worth making a backup of iCal before trying either method, just in case you ever want to revert back to the new leather style.

Show more (or fewer) than seven days in week view

This is a “top sekret” feature that requires a quick trip to the Terminal before it can be accessed. Start by opening the Terminal app (located in Applications/Utilities) then paste in the following line and press return:

defaults write com.apple.iCal IncludeDebugMenu YES

Quit and re-open iCal, and you should see a new Debug menu in the menubar. In this menu, under the Top Sekret [sic] section you’ll find an option to set the number of days in week view to 7, 14, 21 or 28 days. You’ll need a pretty large screen for these options to be that useful.

It isn’t necessary to enable to debug menu to show fewer than seven days in week view. First make sure you aren’t in week view, then just hold down the Command and Option keys and them press and number between 2 and 6.

Open multiple calendar windows

This is another secret feature hidden in the debug menu (see above). Once the debug menu is enabled, it is possible to open up multiple iCal windows by selecting New Calendar Window or by pressing Command-L. This is great if you would live to have two different views open simultaneously — for example separate weeks, or a month view and a day view.

Adjust the font size

It’s now possible to change the size of the text in the calendar view. Just choose Make Text Bigger or Make Text Smaller in the View menu or press Command-minus (-) or Command-plus (+).

Year view heat map

The new “year at a glance” view is fancy, if not altogether that useful. It allows you to see a “heat map” of how many events you have throughout the year, with busier days shown in red and quieter days show in yellow. Double-clicking any month will bring up the month view for that month.

Set as Full Screen

iCal is one of only two apps that I regularly use Lion’s full screen mode with (the other being Terminal). This allows me to leave it always running in the background, out of the way. Whenever I need to check my schedule or reminders, a simple four-fingered swipe to the left will slide the desktop across to iCal running full screen in its own space. To set iCal as full screen, just click the full screen button in the top right corner of the window. You can even combine this with the multiple calendar windows tip to allow you to swipe between multiple full screen calendars that show the current day, week and month.