I can never answer "What did you do last weekend?" Unlike "How are you?" there is no set answer (always a variation of "fine," never the truth). I can't lie and say I did something normal. And I can't tell the truth and jump into a detailed description of what I did do (either special interests or some version of depressively staring at walls/TV/books, decompressing from the week). I freeze on that question. Later, after they're gone, my brain reminds me I saw a movie or something, but it's too late. I try to remember to say: "Not much. What about you?" but I usually forget, just like I often forget "fine" to the "How are you?" question and blurt out something inappropriate and honest.
Of course, I don't WANT to hear about their weekend, too. So...boring....
Anyway, to give the right answers, I have to be fresh and on my social game. If I am off at ALL, I either freeze or say what I actually want to say, which could be about a different topic entirely. Usually I try to go to common areas at work when other people are scarce.
The problem is that what I want to talk about is not socially acceptable; it's not small talk. I can remember the small talk routine if all the stars are in alignment that day, but that's it.
I've decided that I am the weird one at work, and all I can do is try to be nice and do a good job. If they want me to do improv, too, they will have to pay extra.
(That being said, in a boring class, I work on my witty repartee persona with the person I'm next to. If you're into that sort of thing, it's fun. Puns, stupid jokes, rolling your eyes at the teacher. OK, I'm in my 30s, but in school this kind of thing was awesome if the person next to me was cool. I have had a lot of misses though for every laugh I got, though, so it's risky.)