go to the top of a flight of stairs (doesn't even have to be a particularly long flight, just 15 feet vertical or so should suffice), then stand *right* at the edge of the top step (the landing) and look down the steps. I'm talking so close to the edge that your toes are actually off it. Now, lift yerself up as though you are standing on your toes (but obviously you aren't 'cause they are off the step), so you're just a few inches taller than you normally are, and lean out over the steps while looking down at them..
If you do it right, you can kinda balance there clinging to the landing by just the balls of your feet, staring at the steps, and it totally feels like you're falling down them. Kinda vertigo-esque. Not recommended for people with bad senses of balance or wearing shoes with insufficient foot controll/grip (unless you want that "feeling" of falling to be much more pronounced and realistic). :)