My class (Y3/4) have just done their class assembly to the whole school, to which parents are invited. Only had one child who didn't want to be involved (I don't force them) and it went well with a good parental resposne.
To me the assembly is a chance for the children to show what they have learnt and, if I'm really honest, for a bit of positive PR with the parents.
What do you like to see??? What are the bits you hate. It's difficult to be objective from the other side of the fence!!