Stack Exchange Bounty Ad

Setting Up The Environment

Use RVM or rbenv to install and manage Ruby 1.9.3
Run bundle install to load up the gems. This part will likely give you lots of grief due to ImageMagick and RMagick2.
No errors? Fantastic!

Sinatra GO: ruby webapp.rb
Browse to http://localhost:4567/bounty.png?site=apple.stackexchange.com (or click the link if you're lazy, I know I am).
Success!

Feel free to change the site parameter to any fully qualified StackExchange domain.

Via irb or a script in this directory:

require './bounty.rb'
File.open('image.png', 'wb') { |f| f.write(bounty_image(nil, #{number_of_bounties}, #{total_rep_available}).blob) }

I dunno. I think you're done, right?