I'm writing a gem monitor these days. The monitor gem can display ruby methods call stack on browser. It is based on unroller gem, unroller gem prints methods call stack in console, but it is inconvenient to read. So I write the monitor gem to print method call stack to browser.
The repository is: http://github.com/flyerhzm/monitor
And these is a result preview: http://www.huangzhimin.com/images/monitor.gif
It uses sinatra to send data to browser, and the server uses socket to communicate with source codes.
It is just an alpha release, any suggestions are welcome.