My cheap desk lamp has a small rocker switch on the base to turn it on and off. Being a bit budget, the lamp's not particularly heavy and has a tendency to scoot across the desk if you use the lamp from any direction other than head on.
This quick hack uses Sugru
to change the rocker switch into a toggle switch, allowing the switch to be flicked without moving the lamp around.
While just a simple idea for a badly designed lamp, this could be used to greatly benefit those with reduced dexterity, either on similar lamps, inline rocker switches or to change wall mounted light switches into toggle switches.