I maybe too late, but my husband teaches tots how to dance like their favourite popstar - although just turns out to be a great game of musical shapes and a bit of wiggling! Totally adorable and makes them nice and sleepy!
You can find out more about him and what he has done here: www.nmchoreography.com
James Harrington is an excellent magician and great with kids, but would be much more expensive.
However if you fancy doing something a little different, my husband teaches choreography classes for kids as young as 4. It's really good if they want to learn how to dance like their favourite popstar (they can choose their own song too) and it tires them out after an hour!