Hints readers keep discovering clever Mission Control tricks. Once you enter Mission Control in Lion--either by swiping up with three or four fingers, hitting Control-Up arrow, clicking on the Dock icon, or any other means--there are a lot of secrets hiding away in Apple's new mash-up of Exposé and Spaces.
Mission Control organizes stacks of windows by app. Hints reader geoffliang points out that you can get a better view of the windows open in a given app within Mission Control by performing a four- or five-finger spread gesture (the same gesture you'd use to reveal the Desktop when you're in Mission Control). If you prefer a simpler gesture, a simple two-finger swipe straight up over the app you'd like a better look at works, too. When you do that, the visible windows for the app expand and fan out a bit (as seen in the screenshot at the bottom of this article).
Remember, too, that as you move the mouse over the windows visible in Mission Control, you can press the spacebar to see an even bigger Quick Look preview of the window in question. And Hints reader vczilla discovered that you can change which window within Mission Control gets selected by typing the first few letters of that window's title.