Aha! Boston is slyly testing the waters for an Olympic bid. Build a bunch of similar ramps around the stadium, one for SL, one for GS, one for DH, one with a half-pipe, a flat surface around the top for X-C, etc. Ice skating on the floor. They can stage the whole Olympic Games at a single stadium! 'Cept for the stadium seats will be obscured by all the infrastructure, but hey, that's what cameras are for. Then when it's done they can tear it all down and re-use the scaffolding elsewhere.
(They always encourage me to think outside the box, but I don't think they really mean it.)