What projects can I build around subjects during an MCA?

A strong MCA project should solve a clear problem and demonstrate real technical work. A student can strengthen it with proper documentation, testing, source control and a working demonstration. The practical value of subjects becomes clearer when you use it to solve an actual problem instead of studying definitions alone. This point is specifically relevant to the subjects aspect of MCA study. For this specific question about subjects, the practical takeaway is to relate the concept to your own MCA learning goal.