Basically it was an IMAX movie in 3D showing the initial construction of the ISS. It's a lot smaller than the ground based mock ups would have you believe.

Plus membership allows me to feel good about giving money to the Science Museum (free entry now but please give money when you leave) and then allowing me to get in to all special exhibits and IMAX movies for free.

It also give me free access to other science museums around the world (Montreal for example).