Sometimes the best way to learn about a new technology or tool is to find a project that might be interesting to you, start playing with it and why not end up customizing and extending it to fit your needs.
While these days you can find tons of note taking applications for your mobile, desktop or “in the cloud”, I think this usecase is extremely easy to understand and it will allow you to focus on the underlying technologies and not some complicated logic.
Snip = Node.js + Redis ☞
This is a basic application that would allow you to store code snippets and have some syntax coloring when displaying them. Source code is available on ☞ bitbucket.
YourCached.info = MongoDB + Python ☞
Another basic application that allows you to store notes and bookmarks. A lot of functionality you’d expect from such an application is missing and that could be a good excuse for you to play with its source code available on ☞ GitHub and add exactly what you’d like.
I am pretty sure I have missed a lot of similar apps, so please do forward yours to be added to the list. I am pretty sure that building an extensive list like we did for NoSQL Twitter apps or NoSQL-based blog engines will be both fun and useful.