Well, apparently he/she just liked your post!
But, regarding your question, here's one suggestion: you could implement a telephone emulator. For instance, we connect to a server and we have our numbers. You can dial my number and call me. When I pick up the phone, I can talk with you using the microphone and hear you as well. I know there's Skype already, but since it is a project for a college course, I think it will give you some RMI/Sockets knowledge and you'll also learn a new API to be able to use voice in the call!
Cheers, Roberto Perillo
SCJP, SCWCD, SCJD, SCBCD