This has always annoyed me, why does every damn story have to be about the time you and Jack Nicholson saved the earth from the invaders from Planet Kersplunk, or the time you went skydiving while wrestling an alligator in front of the US Senate!?
Look, you have plenty of great stories from your work, your studies or your life in general. Just tell her about the professor that was so distracted he once showed up without his pants, or how you have this coworker with the craziest hair-do you've ever seen. It doesn't matter so much the content, aslong as you tell it with PASSION! If she can feeeeeeel the passion you have about your studies/your work/whatever, then you don't have to fend off the Army of Darkness every wednesday just for the sake of a good story. Be passionate about your subject, and then you can talk about your cat for all she cares.
The other solution: LIE!
Now the trick here is to make the lie so outrageous that she knows you're lying. Example:
HB: So what do you do for fun?
YOU: Well, lately I've been hanging out with Elvis alot, also I'm getting guitarlessons from Hendrix or I can be found shooting hoops with Obama.
Keep it going, making more and more outrageous statements even if she calls you out on them ("No really, yesterday I found a cure for cancer before lunch, I beat Kasparov at chess (of course I played without the Queen so he had a some kind of chance). Remember to be cocky/funny about it.
antic: The girlfriend reply is hilarious and pure brilliance!
