Should a professor require students to attend classes well past their listed times? I'm currently in an undergraduate class that is focused on doing group presentations. This class has a total of around 80 students, in groups of 4. Every two to three weeks we are required to present a 10-15 minute slide show on a specific topic to the class. The issue is our professor does not want people going on different days, because he feels it gives an unfair advantage. On the course schedule the class runs from 1810-1930, however on presentation days he expects all students to sign in at the start of class and sign again at the end of presentations (which seem to run until around 2200).

We've tried to talk with the professor about how late classes are running during presentation days and his solution was to move them to Saturdays from 0800-1200 (but keep the normal class times during the week). He is refusing to break presentations up over multiple days and falls back on the fact he let everyone know this would happen during the first week of class and we had ample time to drop the course.

Is this expected behavior for a large class focused on multiple group presentations? It's too late to drop the course (this wasn't really an option from the start since it's one of the few upper level classes offered this semester), so is this a case of just suck it up and deal or should I bring this up to my department?
The usual advice is to first try to work things out with the professor. In more extreme cases, if you can't work it out with the professor, you should move to their immediate supervisor, which is often the department head / department chair.  

Different universities have different cultures about professors extending class. At some, it would be viewed as normal, while at others it is unheard of. So you should make sure to take into account the culture of your school in that regard.

With that being said, I think you indicated the professor is adding an extra 150-240 minutes per week (if I read the question correctly). That seems unreasonable, in my opinion, and I do think it is reasonable for you to ask for a better way of handling the presentations.  Even if the professor mentioned this in the first week, it is such a large amount to time that it could seem like an unfair imposition. 

One option would be to simply email the department chair. Be very brief in your statement: one or two sentences on what is happening, and one or two more explaining how you have tried to discuss the situation with the professor. Phrasing the email to the chair as a request for advice is one polite way to raise a concern: "Here is what the professor is doing, do you have any advice for handling the situation?" That gives the chair a lot of flexibility in responding.