What is the easiest way to disable the touch pad on a laptop?

Original post isn't real clear on if you need something that can be quickly turned back on or not. Typically, the connector from the touchpad to the mobo is easily reached under the keyboard. You could unplug it as long as you don't need to be able to turn it on/off on the fly (and you're not worried about warranty/possible accidental damage concerns). Obviously, don't do this unless you're quite certain of what you're doing, etc. Poking/proding the wrong thing could cause permanent damage. Insert additional disclaimers here, etc.

The simplest is often the best method. All (almost) windows-based laptops have touchpad / touchstyk running on drivers that are based on synaptics. These are easily accessible from :

Control Panel > Mouse > Choose Tab: Device Settings

Here you can Disable the touchpad.