I’m not suggesting anyone really try / do this.  Mostly this is just to demonstrate how to zoom in and out of an area on your Mac’s screen.  Don’t screw with the Apple Store folks.

Step 1: Find an unattended Mac with a 30″ Apple Cinema Display, or a big 24″ iMac. The bigger the screen, the better.

Step 2: Launch Safari and browse to a website. Any website will do. Something text heavy works well.

Step 3: Hold down CTRL and scroll the mousewheel up to zoom the screen where the cursor is positioned. Scroll to maximum magnification.

Step 4: Walk away.

Step 5: Repeat on other Macs in the store (optional).

Step 6: Watch as dumbfounded Apple Store employees restart the machine, rather than CTRL Scrollwheel down to reduce the magnification to normal.

(Before you flame me, read the comments to see what really happened…)