As TMO’s Jeff Gamet discussed lo these many years ago, an easy way to switch an event to a different calendar in iCal is to pick up the event, drag it up to the calendar list, and drop it onto its new location. This still works in Lion, despite the list being hidden—you’ll just need to pause for a moment as you hover over the Calendars button to wait for the list to pop open, and then you can drop your event on a different calendar at will.
My favorite way to change things to a new calendar, though, is to right- or Control-click on the event in question and use the contextual menu option to choose a different one. That’s so easy to do, it should be illegal in a few states.
And just because I want to wish you all the happiest of Wednesdays, here’s a bonus iCal tip: If you hit Shift-Command-T or choose the menu item View > Go to Date, you’ll get a handy little box that’ll drop down to allow you to type in where in time you’d like to go.
Fifty years in the future? No problem! Want to know what day of the week October 15, 1950 was? Simple. And now you can really set reminders, let me tell you. Don’t go forgetting your granddaughter’s seventieth birthday or anything.