Cucumber lets software development teams describe how software should behave in plain text. The text is written in a business-readable domain-specific language and serves as documentation, automated tests and development-aid - all rolled into one format. Cucumber works with Ruby, Java, .NET, Flex or web applications written in any language. It has been translated to over 40 spoken languages. Cucumber also supports more succinct tests in tables - similar to what FIT does. Dig around in the examples and documentation to learn more about Cucumber tables.
Cucumber is Aslak Hellesøy's rewrite of RSpec's "Story runner", which was originally written by Dan North. (Which again was a rewrite of his first implementation - RBehave. RBehave was his Ruby port of JBehave). Early versions of the RSpec "Story Runner" required that stories be written in Ruby. Seeing how much this sucked David Chelimsky added plain text support with contributions from half a dozen other people.
In April 2008, Aslak Hellesøy started the Cucumber project to address the internal design flaws and usability problems of the RSpec Story Runner (Yes - Cucumber also has warts on the inside). Joseph Wilk and Ben Mabey joined as regular contributors when Cucumber was just a little Gherkin. Matt Wynne joined the Cucumber team in September 2009 after. Mike Sassak and Gregory Hnatiuk joined in October 2009 after their great work on a faster parser for Cucumber. In addition to the core team over 2000 developers have contributed patches, bugfixes, tears and joy.
Cucumber's plain text DSL (Gherkin) somehow came out from the Agile community, mostly based on distillations made by Dan North, Chris Matts, Liz Keogh, David Chelimsky, and dozens of people on the RSpec and Cucumber mailing lists. And Aslak.