My current project is my favorite. It's health care related, so I can't provide a link. However, it's a case and disease management system that lets nurses work with chronically ill patients to help them manage their diseases and hopefully have good results (not always possible, sadly.)

Ground up, green field development. I should say, WAS my favorite. Nowadays, no more innovation. It's all about adding features to meet requirements of external entities. But still, quite proud of it.

I'm the sole developer. I have a nurse counterpart who I work with very closely during development. She's a primary user of the system and the main source of feature requests (though not the only one).

This project includes many things I've never done before:

• Using OpenOfficeXML to create Microsoft Word documents programmatically
• Implementing two-factor authentication
• The main screen area where nurses work is, in reality, a single-page application. Didn't start out that way, but that's what it's ended up as. This continually presents many challenges.
• Back end queue system for file importing and processing
• Nightly job system for doing certain tasks
• Integrating with Exchange, Office365 and IMAP to read through emails to gather emails to and from patients to attach them to patient records for easy access
• More that I can't recall at the moment... there's five years' worth of development in this system.

This project continues to challenge me in many ways.

I'm really liking designing a programming language and the compiler for it. It's pretty useless since no one will use it, but it's very educative.

This one, by far. Such a shame they pulled the funding plug a couple of years later, though the region is still there thanks to the generosity of a tech university in Singapore.

oucs.ox.ac.uk/ww1lit/secondlife