I know that this is a bit sad, but my best gizmo, in terms of usage and practicality, is a "Third Hand" chart clip. It is a piece of spring metal, attached to a length of broad elastic with a clip on it. You simply attach it round your thigh (Ohh err missis!) and stuff your quarter-mil into it. Stops it falling off the pax seat. Only cost me $3.50! Otherwise, my other gizmo is a hand held GPS.
Blue skies!