Magnetic force does no work

I was at an MNSTA conference in the spring when I sat in on a workshop showing off a few different labs students could do (run by Steve Ethan of physics day at Valley Fair fame).  One of the labs involveds magnets and someone asked how much work it was to set it up and I quipped that magnetic forces do no work.  What was interesting is that whereas at Hamline my students would dutifully nod their heads, at the workshops the teachers pounced on the comment and asked how one magnet could pull another.  I think that's a great question and I can't wait to take it up in next semesters class on Electricity and Magnetism (PHYS 5940, I think).  The book I've chosen (by Griffith) does a great job of talking about how B-fields do no work with a few different examples.  Hopefully I'll be better prepared at the next MNSTA meeting!