We just went to a play group this morning, and my very active 13 month old twins were more interested in greeting the other children than in sitting still. At the end of the session, one of the helpers explained to me that they need to be sitting quietly with me so that they don't distract the other children (it's a 0-4 playgroup) 
. I asked her if they were really meant to be able to sit through 30 minutes of stories at that age, and she implied that my children might just be later on the learning curve and asked if they sit through bedtime stories either... which they don't (it's more of a calisthenic story time).
A I being really dense for not realising that they were meant to be able to do this by their age? And how on earth do I train them to do it? It's nearly impossible with two as I can't just go chase after one without then losing the other and spending most of the hour playing whack-a-mole. :(