Yeah, and maybe while watching one a mission triggers. Like if something entered the arena (maybe a dragon or daedra or god knows) and you rushed into fighting it. And that would lead to an arena on a plane of oblivion, with enemies we've faced before and more, like Xivalai, Spider daedra, and maybe a daedric-feeling dragon. The daedric realm arena should be big enough to hold a battle against a dragon. Maybe like windhelm, whiterun and solitude together... but it'd still be awesome. And as rewards there would be daedric based dragon shouts and weapons like goldbrand, daedric crescent, umbra and many others!