Ha ha, good quote part.. Uma Thurman is hot in other films too, now John Travolta is definitely hotter in Grease and some other films!!
I really like conversation, especially if it's about interesting things, with interesting people.. Or if you at least have a good goal with it - eg 'network for eco projects' or 'find out what this person thinks about XY' or 'find out more about ZWY'...
even getting to know someone and what they like or dislike, or learning new things is a good goal.. maybe this approach can help?
often people with SA/shyness focus too much on themselves/ourselves, it's important to kick those thoughts away and focus on the other person and what they are saying.. maybe just say, 'uhm', 'aha', 'oh dear' or such, so they feel heard and listened to... 'okay', 'interesting', 'cool' (when used properly!! listening essential!!)... or 'that's weird' or 'I never really thought about this' or 'who would have thought?' or 'I've never heard this before' can be good too
You can also try to sum up their thoughts/feelings/what they just say - 'So you're saying that you think Peter is cheating on you?' (try not to be obvious and use your own words when paraphrasing) Of course use it appropriately.. not for every day 'easy' things usually, maybe for some more complex conversations, just to make sure you understood it right.. especially if you're not completely sure what they were trying to say..
You don't even have to talk much and people can think you're a good listener and great to talk to!!
There are books that can help, in the old times young ladies and gentlemen were taught 'the art of conversation' too - I think that was a good thing!! (How to change topics etc. I never knew you could 'change topics' until I read about it in a book!

)
Also, are you in front of computer too much? 5+ hours a day can 'fry your brain' a bit (okay, not exactly that, but according to a study it causes depression and problems with memory/concentration).. so this would make it more difficult to converse too..
Or any iffy nutrition? - too much artificial food additives or soda pops or such can do weird things to your body and your brain too...
Is it better after a walk/jog in nature? (You could try?)