Depressing Call

I get a call from my dad, (he is in prison) every Wednesday. The biggest problem is he is so happy to speak to me, wants so badly to heard about my life. Unfortunately, all I have to say is "yea debate", grades and I am eating.  I want to do somethings solely so I can be like I'm doing X and Y went to see blah.

But i've got nothing, so the conversation cuts short. And I don't know how to stop it.