I was thinking the same thing. I remember reading about some guy who took a bunch of the disco ball mirrors and glued them to the dish and put a steam generator (coil of copper pipe basically) where the antenna was. He used the pressure to drive a steam turbine or engine and got a few KW of power, as long as the sun was shining and he continued to "steer" the dish to point at the sun all day. If I remember correctly he used a fluid that evaporated at a lower temp than water to help get more power from the heat.... but that was a while back and I have a memory leakage issue.
Or do what we did and bury it for the base of a fountain/water feature. It made for a nice round dish to put the fountain in the middle of, but ours was an old solid style and not the mesh kind.