I've got some:
Q: What is the CS50 appliance?
A: The CS50 Appliance is a "virtual machine" that allows students easy access to the tools needed for the course. It equates with running a computer system inside your current one. Instructions for installation of the Appliance can be found here.
Q: For CS50x 2015, do I need a new version of VMWare or other Virtual Machine software?
A: No. Simply follow the instructions above to download and install the new appliance.
Q: Is use of the Appliance required?
A: While not required, using the Appliance is highly recommended to make setup for the course easy and hassle-free.
Q: I didn't finish CS50x in 2014. Can I resubmit my old problem sets?
A: Yes, but be aware that some problem sets are different this year.
Q: What should I do if I feel stuck/discouraged/unmotivated?
A: Take some deep breaths and reach out to your classmates via CS50x Helpers, Facebook, Reddit, CS50 Discuss, or Twitter. Many people are willing to help you, and we don't want you to give up.
[ ^Okay, that one was a personal answer, and I can't speak for everybody, but I think it might be a good one to have there :) ]
Q: I have been working on the course and have grades for the psets (and perhaps the final project), but the edX Dashboard still shows my grade as 0%. What can I do to resolve this?
A: Rest assured that CS50 does not use edX's built in Gradebook, but rather its own, and therefore you do not need to do anything. You can safely ignore this discrepancy.