I guess it's how you define a henge and whether you view henges as being frozen in time or a monument that was being altered by different generations. The enclosure-long barrow-cursus-henge-alignment thang.
An example would be Stanton Drew where you had a possible circular ditch enclosing concentric post rings - (seems pretty henge-like to me), which then evolved into the Great Circle. I'm sure there are better examples by my aunty stella arrived a while ago

As for later use, the best known example is the evolution of the village of Avebury - 'lets put a boozer in the middle of the henge and a church on the edge' - them boys knew a thing about town planning.
King Arthurs round table & the Little Table appear to have been some form of sports arena in the time of Stukeley,(if his sketch is to be believed) King Arthur's has also been used as a tea garden.

There is Maumbury rings in Dorchester which had its banks enlarged by the romans to create an amphitheatre. It was then used to hand people and as a gun emplacement during the war (presumably 2).

Its now used as a hang out for the local kids :)