Chess player
In the early times, chess used to be the prime example of artificial intelligence. Nowadays, some chess programs can beat a human master, and simple implementations can be written in a few pages of code.
Chess player is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Write a program which plays chess against a human player. No need for graphics -- a textual user interface is sufficient.