The other answers suggest deflecting the interaction in some way, and that's alright in scenarios where you really can't talk because you have something to do. But you can't do that all the time and anyway you're saying that you simply DON'T WANT to make smalltalk.
What I think you're missing, however, is that the smalltalk is not intended to actually probe what you did last weekend, or whatever trite subject the smalltalk is about.
The point of smalltalk is to develop rapport. For many people it is important that they don't have the feeling that they're working with strangers. The smalltalk is a way to make a human connection. You don't have to try to precisely answer the questions or ask carefully considered questions (it is not like stackexchange). All you have to do is demonstrate that you're engaged with and empathetic to the concerns of the people you're talking to.
When you're asked a question about what you did over the weekend, it is not expected that you literally describe what you did in any kind of detail. All you have to do is say something nice or funny or interesting. You have a lot of latitude in whether or not what you say has anything to do with last weekend or not.
Instead of finding ways to get out of smalltalk, accept that it is a reality of interacting with coworkers and perhaps don't take the smalltalk too seriously in terms of answering "the questions" in the dialog.