(Please note, the above photo shows the 1st version, the current version on sale has had some small updates.)

DEBUG-U-MUG is a programmer's quick reference or cheat sheet... on a mug!
It's packed to the brim with quick ref info including:-
  o a Binary, Hex, ASCII, decimal, and signed decimal (Two's complement) conversion table for 1 byte values .
  o max and mins for integer variable types, and an approx. conservative max for floating point types.
  o commonly used short cut keys, for debugging using Visual Studio and Xcode.
  o frames per second to milliseconds
  o pi/2, pi, 1.5pi, 2pi.
  o simple colour mixes
  o trigonometry formulae in all permutations in programmers' format.
  o a degrees, radians, gradient, sine, cosine conversion table.
  o bit values for 32 bits integers in decimal.
  o some useful unicode codes
  o and more.
The conversion tables are especially good for when debugging because the information you see in the debugger is not always what you're most familiar with...
for example if you are examining variables that give angles in radians you can better visualise the angles by glancing at your DEBUG-U-MUG and seeing approximately what they are in degrees... no need to keep tapping them into a calculator to get the degrees.
Likewise, if you're looking at some bytes (char) in the debugger sometimes they may be displayed as signed when you wanted them as unsigned or vice versa, so you can just look on your mug to see the proper value, no need to hunt round the debugger's sub menus to get it to change the display format.