Recently the group that coordinates the Penn interviewers asked that we volunteer to interview those applicants that had not received an interview. These new assignments have to be completed by 3/1 while the earlier assignments were to be completed by 2/16. The new assignments will be conducted by phone or skype.
If you have not had an interview check your email & spam folders - you might have a note.
(I live on the west coast and my new applicants are on the east coast; I emailed them info about the interview, gave them various dates and times for the interview, and to introduce myself.)