I'm pretty sure a hash, in the ruby context biz2hack has come across it, is best explained as a dictionary. It's an object that maps a set of keys to corresponding values. So you could have a hash that maps fruits to colors {:banana => 'yellow', :strawberry => 'red'} or people to occupations {'Steve Jobs' => 'CEO', 'Barack Obama' => 'President'}

http://www.ruby-doc.org/core/classes/Hash.html

Behind the scenes, ruby is using a hash function to implement the hash data structure, just like jacquesm says, but don't worry too much about that.

I jumped into rails development about a year and a half ago with minimal programming experience, so it's definitely doable. Good luck!