While you're a moving discothèque, why not invoke the wrath of road raging drivers all around you, too? Enter the Drive E Moticon LED Car Sign.
As the Web site says, this device signals your displeasure "when a single finger gesture can perfectly express your sentiments to a fellow vehicle operator." The battery-powered LED screen is attached to the rear window of the vehicle and is controlled wirelessly by remote control. The user chooses between five functions: sad face, happy face, 'thanks', 'back off', and 'idiot.' To our displeasure, you can't customise these functions.