I feel s-o-o-o-o-o delightfully geeky! I don't know if they (and yes, there are two) are still available or not, but they used to be because I've got them on CD. The first is called Star Trek: Spock vs. Q
and the second Star Trek: Spock vs. Q -- The Sequel
My copies are from Simon & Schuster Audio and they are productions of a Nimoy-de Lancie company called Alien Voices.
I also have a third title from the same production company that is a dramatization of Journey to the Center of the Earth
(starring Nimoy, de Lancie, and Roxann Dawson, among others). This one is still available from Amazon -- I haven't taken the time to look for the others....googling, googling...Ooh, I just found this:
It looks like I need to do a little shopping...