The Power of the Calculate Tool

Just a little curiosity I discovered today. I've been working with a Python script that has some problems calculating a field using an expression. I figured out that the problem was the syntax used in the expression is treating a variable as if it were a field in the feature class (but it is not a field). This was obvious to me because the variable in the expression is surrounded by Python decode field characters (the exclamation mark).

Anyway my search landed me on this page.
http://blogs.esri.com/Dev/blogs/geoprocessing/archive/2009/03/06/Tips-and-tricks-_2D00_-accessing-feature-shape-in-Calculate-Field.aspx. I don't recall ever using this tool but I find the ability to convert the units to any of CENTIMETERS | DECIMALDEGREES | DECIMETERS | FEET | INCHES | KILOMETERS | METERS | MILES | MILLIMETERS | NAUTICALMILES | POINTS | YARDS by simply specifying this with the @ symbol absolutely fantastic !!!