Perhaps I'm misunderstanding your posts, but you seem to be acting rather harshly. It seems as though your mum is doing this because she wishes to spend time with you. Is it really such a crime for a mother to want to spend time with her child with whom, according to your second post, she used to be so close? More than likely, she is hurt you don't invite her places and is trying to guilt you into inviting her by mentioning she can't go to these places. It's supposed to serve as a reminder you didn't invite her. This method may be aggravating, but it is not at all uncommon. Every mother on the planet will pull at their child's-and husband's/wife's-guilt-strings now and then. One must look at the reasoning behind why the mother is using this method.
I would guess her constantly going places you are likely to attend, despite not having an interest in those things, is done in the hopes she will bump into you. Or perhaps she is taking an interest in these things so that you two will have something in common and will, therefore, spend more time together. Again, I don't think this is all that baffling. She wants to spend time with you. You won't spend time with her.
I'm not saying you should spend every waking moment with her, nor am I saying you are obliged to invite your mother everywhere you go. I do, however, believe you should talk with your mother about this behavior so that there isn't so much bitterness between you two. If she tends to smother, let her know. Set clear boundaries. Also, don't cut her out completely-she's your mum, after all.