Hi.
Can anyone suggest a project idea or some open source project for a small group of students (3-5). I want them to learn how to work in team (VCS, unit testing, continuous integration) as well as to practice in design patterns implementation.
P.S. Java or C++.
There are many opensource projects out there in codeplex.com, I believe you should be able to find the topic that interest your students there.
How advanced should the topic be?
You could work on a new algorithm in order to allow the Garbage Collector to gracefully handle big heap memory.
In 2009, Patrick Dussud made a great videocast about .NET's garbage collector. That could inspire you since Java is facing the same sort of problem in big memory context.
One project I enjoyed in college was creating a unix mini shell. We did this in C but Im sure it would transfer to C++. It was one of my most challenging programming courses during my time in college. The project started small and with each assignment we added new features to the shell very SCRUM like.
"Make a game" can be very fun. It's not exactly a "classic business application," like you said you wanted, but hey, suggestion.