Thanks for the tip about "Screen Saver - Hot Corners". Same instructions at http://support.apple.com/kb/HT2485If you use hot corners, you can set a corner to put the display to sleep (when you move the cursor there). Not a dumb question, I've heard worse
Go to System Preferences -> Mission Control -> Hot Corners (at the bottom) -> then set a corner to put it to sleep. Then drag your mouse to that corner. To wake it up, just click or hit a key. Simply moving your trackpad wont work (don't think moving a mouse will either), which is new to Lion.