Jekyll on Heroku build with sprockets like assets pipeline and coffescript and sass compilation.
Here's a clean jekyll-heroku-starterkit on heroku http://jekyll-starterkit.herokuapp.com/.
jekyll-heroku-starterkit is configured and bundled to work with Heroku without additional configuration, just create an application and push.
jekyll-heroku-starterkit uses jekyll-assets plugin. It's sprockets assets pipeline known from rails configured for Jekyll. For usage visit https://github.com/ixti/jekyll-assets/8.
Heroku free dyno goes to sleep. Dynopoker gem runs a process that pings itself. All you need to do is change address in _plugins/dynopoke_config.rb.
As far as Jekyll is concerned - it's business as usual, for more info visit Jekyll website.