Bolt is an open source static site generator written in Ruby. Bolt was created as no current static site generators could execute code dynamically at site compile time — with Bolt at compile time you can pull in records from your database, make http requests, prompt the user for information, etc.
There is a tutorial here which I hope is useful. If you have any comments/questions/suggestions just send me a mail at firstname.lastname@example.org or Twitter me @benofsky. If you find a bug or have a feature request please open a Github ticket (tabs above).