We've been out of the social loop for about 5 months due to my being uncomfortably pregnant, then csection recovery and new baby adjustments. We are now venturing out and it has been pretty bad. We went to two toddler activities this week. At each one DD ran around like a maniac the whole time. On Tue we went to a craft activity that began with story time. All other toddlers were sitting nicely on the floor listening, she was running around and wanting to see and touch everything. I handled it by getting down on her level, making eye contact and telling her I needed her to sit and listen to story. On redirect two I pointed out how all the other kids were sitting nicely and told her I needed her to sit nicely too. The third time I told her if she couldn't sit and listen then we would have to leave. We wound up leaving. She wasn't upset and didn't seem to understand that she was missing out. Today we went to Kindermusik. She literally ran in circles around the room. Again, i got down on her level I told her what I expected. On time three I removed her from the classroom and told her if she didnt do what I asked we would have to go. Again, we wound up leaving. I don't know how to teach better listening skills and following directions. I'm not so much for spanking. I don't know what else will get through to her. Making her miss out on a fun activity doesn't seem to be having a negative effect as a consequence. What next?

Re: Tips to help 26m old listen? What to do when it doesn't work?
It doesn't seem like she thinks those are fun activities if she is not participating and doesn't care if you leave. Since those are extra activities and not, like, mealtimes where she DOES need to sit down nicely, why not just skip them? She obviously doesn't love them.
If you have a new baby at home I would venture to guess she might be feeling cooped up and the last thing she wants to do is more still/quiet/calm activities. Can you go to the park instead? Have playdates where she can run around?
I realize that's doesn't really address the listening and following directions issue, but that's what stuck out to me in your post.
Does she routinely follow directions at home? It almost seems like she didn't understand since she couldn't have cared less when you left. If she's not understanding instructions, this is something you should talk to your pedi about.
If this is an isolated incident--paying attention to a craft or story in a group setting is something that has to be learned with many kids. I would avoid classes where teh expectation is to sit for an extended period of time and start slowly. I would literally make her sit in your lap by snuggling her and offering praise for sitting nicely for short periods.
Is her attention good at home to activities? I wouldn't let her run off whenever she's bored of something--really encourage her to follow through and finish an activity instead of constantly running around and just doing what she wants. Do hand over hand to get her to finish if she will not and offer praise when she does. Start small and work your way up.