Cool

Slapp: A simple chat wall Merb tutorial is a perfect example of the sort of tutorial / guide that could encourage a lot of people to try out a new framework (as far as Merb is new, of course). It walks you through the process of developing a "chat wall" type application with Merb from start to finish (right from installing Merb to playing with the running application).

RubyAMP: Amazing Ruby Bundle for TextMate

REST Client - Simple DSL / Ruby Library for Accessing REST Resources

Rush, by Adam Wiggins, is an interesting development. It's a shell and remote login (as with SSH) replacement written in Ruby that accepts Ruby syntax to perform system operations. Consider these operations:

License: CC Attribution Credit: conner395 @ Flickr