Stranded in a taught MSc CS Program. What should I do?
Be proactive. Identify the professor(s) that could be your thesis adviser and keep  asking for advice on how you can participate in his or her research and how he/she can officially become your adviser. You could also talk to the department chair.

In the mean time you could look into participating in some open source project, which could score some bonus points for you when applying for PhD or internship.

Another option for bonus points and priming your skills is participating in (programming) competitions that require more than just coding skills but analytical and creative thinking as well.

If all else fails, consider applying for a different school, although this may mean time lost. On the other hand, I did retake several classes while in a grad school although I already had a MSc, which was well worth the time spent, offering deeper and more research oriented perspective on the subjects.