About T-Shirt Design
If you like shirts that actually have some personality, The 2nd Amendment A Well Regulated Militia Being Necessary To The Security T-Shirt is a good example. Anyone who is into everyday humor will probably understand the idea right away.
You could wear it for casual days, bring it out for birthdays, or just keep it in the normal shirt rotation. The graphic tee style keeps the whole thing casual and easy to understand. It has the relaxed feel people usually want from novelty shirts without getting too complicated. The whole point is to get a laugh, and the shirt does that without making things complicated.