This script will clip any drgs in the map by creating a new file named clp+name of drg in
the folder that contains the original drg.  The original will be replaced by the clipped one
in the map. This hasn't been thorougly tested, so I'd appreciate any input at
jswi@lycos.com.

Make sure the Spatial Analyst is activated.
In ArcGIS, from the Tools menu, select
Macros and the Visual Basic Editor.  On the left side of the
Editor, right click on Project and select Import file.   Navigate
to the .bas file you extracted from attached zip file and close the
Visual Basic Editor.  With the DRGs you want to clip loaded into
the map, select Macros from the Tools menu and choose Macros.  In
the macros window, highlight the *.drgclipper (make sure Project
shows in Macros in box) and click Run.  Please let me know if you
have any questions or problems.