Many people experiment in college; I experimented with software architecture. Over the course of a few years in college I hacked on a component-based GUI Win32 C++ instant messaging client that interoperates with AOL's proprietary OSCAR protocol.

At the time, there were few quality IM clients on the Windows platform. Most were either unable to use all of the features of AIM, or had subpar UI. (Unfortunately, this situation hasn't changed much.)

OpenIM uses a publish/subscribe architecture to minimize coupling between components. This results in components that are smaller, easier to reason about, and test. For example, the AIM protocol component has no knowledge of any UI; it merely responds to method calls and sends out events (such as AccountConnectedEvent) as they occur. The EventManager is responsible for distributing Events to registered components. Partitioning features along component boundaries makes development incredibly pleasant.

(Also, the use of CRTP in AccountEvents.hpp should induce the Inception theme in your head.)

I graduated, and became more social. Regardless, I thoroughly enjoyed the late nights spent hacking on it, and do believe it is possible to make nice software, even in C++.