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There is an interesting 2D programming language called Befunge. fungot is an IRC bot written in the Funge-98 version of the language. As far as I am aware, it's one of the largest hand-written Funge-98 programs there are.

Features of fungot include interpreters for the brainfuck and Underload languages, support for user-defined commands in the above-mentioned languages, as well as an ngram-based babble generator with various styles. Most of the time you can find fungot on the channel #esoteric in the freenode IRC network. It also has a periodically active Twitter account.

The main source file is fungot.b98. The GitHub repository there also contains some other files necessary for running it.