Disable those pesky hot corners when you don't want them and easily reenable them when you do!

Mac OS X Disable Hot Corners

-- By Richard Kulesus, 2009.  Released without license!
-- Use this for whatever!
-- I seriously despise code authors who copyright tiny bits of obvious code
-- like it's some great treasure.  This is small and simple, and if it saves
-- the next guy some time and trouble coding applescript I'll feel good!
--
-- Quickly change all the hot-corners to do what you want.
-- Particularly useful for presentations and full-screen games.
-- Customize the activity of each hot-corner with "all windows/application windows/dashboard/disable screen saver/none/show desktop/show spaces/sleep display/start screen saver"
-- The MODIFIERS are the keys which can be used to supplement hot-corner activation.
-- Here I've set them all to {}, which is none.  Options are "command/control/none/option/shift"
-- Dashboard in a fullscreen application.
--
-- Version 1.0
--  - Initial release
--

tell application "System Events"
	activate
	if UI elements enabled then
		tell expose preferences
			set properties of the top left screen corner to {activity:none, modifiers:{}}
			set properties of the top right screen corner to {activity:none, modifiers:{}}
			set properties of the bottom left screen corner to {activity:none, modifiers:{}}
			set properties of the bottom right screen corner to {activity:none, modifiers:{}}
		end tell
	else
		tell application "System Preferences"
			activate
			set current pane to pane "com.apple.preference.universalaccess"
			display dialog "UI element scripting is not enabled. Check \"Enable access for assistive devices\""
		end tell
	end if
end tell

tell application "System Preferences" to quit

Mac OS X Enable Hot Corners

-- By Richard Kulesus, 2009.  Released without license!
-- Use this for whatever!
-- I seriously despise code authors who copyright tiny bits of obvious code
-- like it's some great treasure.  This is small and simple, and if it saves
-- the next guy some time and trouble coding applescript I'll feel good!
--
-- Quickly change all the hot-corners to do what you want.
-- Particularly useful for presentations and full-screen games.
-- Customize the activity of each hot-corner with "all windows/application windows/dashboard/disable screen saver/none/show desktop/show spaces/sleep display/start screen saver"
-- The MODIFIERS are the keys which can be used to supplement hot-corner activation.
-- Here I've set them all to {}, which is none.  Options are "command/control/none/option/shift"
-- Dashboard in a fullscreen application.
--
-- Version 1.0
--  - Initial release
--

tell application "System Events"
	activate
	if UI elements enabled then
		tell expose preferences
			set properties of the top left screen corner to {activity:all windows, modifiers:{}}
			set properties of the top right screen corner to {activity:all windows, modifiers:{}}
			set properties of the bottom left screen corner to {activity:show spaces, modifiers:{}}
			set properties of the bottom right screen corner to {activity:show desktop, modifiers:{}}
		end tell
	else
		tell application "System Preferences"
			activate
			set current pane to pane "com.apple.preference.universalaccess"
			display dialog "UI element scripting is not enabled. Check \"Enable access for assistive devices\""
		end tell
	end if
end tell

tell application "System Preferences" to quit

I don't have any OSX devices anymore. Thanks for the link @hng.

Whats "activity" parameter for sleep monitor?