GLaDOS (Portal 2) voice changer recommendation?

I'm not sure that you can do this in real time, unfortunately. Her voice is highly processed using formant shifting and manipulation of artifacting to get it to kind of slide up and down but still be robotic. It is demonstrated in this video.

If you know any music production techniques or programs, you could get a similar effect by using the Mac's built in speech synthesizer and an Auto-tuner similar to what you hear on pop radio nowadays. Instead of automatically figuring out what pitch you're trying to achieve, you'd need to "force" it from one pitch to another by feeding the Auto Tune program a parameter - so if you're talking in the pitch of C, you get the GLaDOS effect by forcing it up to G or A. Again, not a super easy task to do in real time.

Wait, I started playing Portal 2 last night and ignoring my girlfriend. Am I going to get a call later?