A List Apart, Rapid Prototyping with Sinatra:
Sinatra is a kind of web designer’s swiss army knife. It doesn’t take long to learn, it comes in handy for prototyping bigger projects, and it’s also great when you need to get a web app running quickly without dwelling much on the back end.
I didn’t know about Sinatra before. I’ve been meaning to learn recent web technology, just to exercise the mind a little bit — and Sinatra is intriguing. Small enough to learn without a huge investment, but powerful enough to be useful.