Macos – Changing dual-monitor settings without closing the laptop lid on OS X

I have a Unibody MacBook hooked up to an external display. By default when I boot up, the system will go to dual-monitor mode. I want to use only the external display.

The Apple supplied solution to this problem is to close the lid of the laptop which puts the machine into sleep mode and then move the mouse around to wake it up again. Because the machine is being woken up with the lid closed, when the displays are detected the system finds only the external. After the system is functional again, you can open the lid if you want and the laptop screen will be non-functional until you either tell the system to detect displays from the system preferences or you turn off the external display.

Every time I want to use only the external display, I must reach my hand over to close the lid, wait for the machine to sleep, jigger the mouse, wait for the machine to wake up, and finally open the lid again because I don't want the machine to overheat. I feel that this is very stupid to have to do. Why is there no button or menu option that says "don't use this screen"? Is there any third-party software way to change the screen setup that does not involve physically closing the lid and playing a game of "are you sleeping" in order to switch such a simple software setting? We are in the 21st Century and honestly this is childish.