An auto-refreshing Twitter and/or Identi.ca hashtag client. You can find it live at Heroku.
Make sure you're using Ruby 1.9.x. I suggest using RVM for managing different Ruby versions. On the command-line:
git clone git://github.com/hleinone/hashfresh.git hashfresh
cd hashfresh
gem install heroku
On the command-line:
gem install sinatra haml maruku
ruby hashfresh.rb
On the command-line:
heroku create <YOUR_APP_NAME>
git push heroku master
Trying to find the version for Google App Engine?