To be honest, I wouldn't rearrange my schedule to see this. It's a small exhibit (just Gallery 1) with items from the museum's own collection. The idea was to put together items related to the Olympics. There are some ancient things, and some more modern.
If this is any barometer, I'm at the Legion once a week and I've only felt the need to see this exhibit once.
On the upside, Gallery 2 has been reinstalled after many months of various special exhibits (Mourners, Roman floor, etc) so if you enjoy late Gothic/early Renaissance those things are back.
There isn't a large special exhibit at the Legion until mid-November when "Treasures from the Louvre" opens. However at the de Young now is the William Paley "Taste for Modernism" and Nureyev's costumes -- both are excellent and $20 gets you into both.