Progopedia, the Free Encyclopedia of Programming Languages

Progopedia is a free, wiki-style web encyclopedia of programming languages, licensed under the GNU Free Documentation License, edited by registered volunteer contributors. It catalogs entries for languages, dialects, implementations, and versions (currently over a hundred languages and hundreds of implementations/versions), along with example programs like Hello World, Fibonacci, and Factorial in many languages. As a young, community-editable project, its coverage is uneven and expands as volunteers contribute articles.