Sometimes just responding with an "oh"(in a nice sound) helps. My mom seems to have a lot of drama too and I have learned by responding like that helps a ton. I still hear her stories, but I don't respond like I am interested in them. I've learned that just fuels the fire.
My SIL on the other hand will continue with her drama stories even after the whole family pretty much ignores her crazy (and I mean crazy) stories. We usually only have to hear her stories just once, but every single time we see her, it's a whole new story that you couldn't even make up yourself if you wanted to. Drama, drama,drama,drama,drama,blah,blah.
I bumped into her yesterday and the for the10 mins I saw her, I learned that her oldest daughter was sent by ambulance to the hospital for asthma (she's 21). I didn't even know she had asthma. And her teenaged son is trying to get over his migraine to see if his sister is dieing of asthma, lol! This is probably the tamest story, but she even has drama when she unexpectedly runs into someone.
Some people you just can never tame!! Good luck to you, it will get a td bit better, but will most likely always be a part of her.