A big part of what got me into AutoCAD was learning how to mess with people. This is a classic for me. There is a file called base.dcl that is used by some dialog boxes as a template. With some simple editing you can change the "OK" and "Cancel" buttons of the dialogs that reference base.dcl to reflect a little cooler lingo.
Open base.dcl with Notepad and find the section below and alter as required. Save and close, then enjoy.