As a way to learn node.js and to get familiar with Heroku I recently built 99thingstodiscuss.com. Its a simple piece of software that randomly outputs a topic for conversation between two prospective partners.
It works fine on a desktop but is primarily meant for mobile devices which is why it looks rather sparse.
It was a good learning experience and, in my opinion, its easy to leap into marriage without having had serious conversations about important topics. Learning new technologies and solving relationship problems. Look at me go.