Stonehenge 181
Image by Snap

Play match the potsherds
http://www.wessexarch.co.uk/learning/games/sherds/sherds.swf
Or design a BA beaker, Amesbury Archer style
http://www.wessexarch.co.uk/learning/images/resources/Beaker.pdf

H Hob

or this
http://www.amazon.co.uk/Build-Your-Stonehenge-Running-Press/dp/076242883X
apparently has 'a little easy to understand book about the stones'.