Kind of like this: Got any Mac OS X hidden features or nice tips & tricks? but specific to OS X Lion 10.7.x ONLY
Do you know any hidden or little-known nice feature of OS X 10.7 (Lion)? It doesn't matter what it is—maybe just a short terminal command. Share your experiences on hidden OS X features here.
Please post one tip per answer. Please also check to see if your answer has already been posted - duplicate answers will be deleted. To search the answers of this question you can use
inquestion:this, directly from the question page) in addition to your search terms in the search box in the upper right hand corner of this page.
Also provide details on how to achieve that feature, and if possible, include a relevant image too!