If you want to use your MacBook with another display, or want to use it with your LCD TV to see a movie, you probably want to close the lid to your MacBook.
I’ve recently acquired a 22″ LCD monitor and I’ve connected my MacBook to it with a Mini DVI to DVI adapter.
After you connect your MacBook to your LCD, go to System Preferences, Displays, and select the Mirror Display mode.
Plugin your mouse and keyboard into your MacBook USB ports and then you can close the lid to your MacBook.
The MacBook will go to sleep, don’t worry… now take your remote and press any button. The MacBook will wake up even if its lid is closed.
The post that helped me do this is here.