Culturally Authentic Pictorial Lexicon: authentic images for language learning - connecting language, culture, and meaning. Authentic photographs arranged by language and context.
devcheatsheet.com: Cheat sheets for developers - many program languages, markup languages, query, libraries / frameworks, operating systems, version control, servers, databases, etc.
Snipplr: a free code repository that allows you to store all your code snippets online and share them with others. You can even have access to the code shared by others.