Brainfuck

Brainfuck is a Turing-complete programming language that can be implemented with the smallest possible compiler. The language has eight statements that perform pointer operations.

Example: Hello World

++++++++++[>+++++++>++++++++++>+++>+<<<<-]
>++.>+.+++++++..+++.>++.<<+++++++++++++++.
>.+++.——.——–.>+.>.

The programs tend to be a little on the complicated side. The programs can be run on a turing machine, which can accomplish any computing task.