Digital Data Services, Inc. (DDS), a company based in Denver, Colorado, put together a very helpful ArcGIS Reference Card for the 2006 ESRI User’s Conference.
It includes common map scales, a UTM diagram of the continental United States, ArcMap editing and troubleshooting tips, and some basic Visual Basic functions and is available for download as a .pdf at the Neer Cartography website. This could be especially useful to those who only occasionally dabble in the ArcGIS Desktop environment.