Hello World Shirts
A "hello world" program is a software program that prints out "Hello world!" on a display device. It is used in many introductory tutorials for teaching a programming language. Such a program is typically one of the simplest programs possible in a computer language. A "hello world" program can be a useful sanity test to make sure that a language's compiler, development environment, and run-time environment are correctly installed.(From Wikipedia)
Check out ACM's Hello World Project
