Ruby is a dynamic, open source programming language with a history dating back to the 1990s. It was created by Yukihiro "Matz" Matsumoto as a language that balances simplicity and complexity. Some key aspects of Ruby include its philosophy of putting people over computers, its flexibility through multiple approaches, and its popularity in areas like web development through Rails. It continues to evolve and see adoption in fields like QA/testing, DevOps, and general programming.