Complex sentence: The event is organized for the enjoyment of rich spectators, who place bets on who will survive, one of them being Jasper Bagges (Jason Statham), who bets on his brother Ronald (Ray Winstone), who was brought from the mental institution.
Split into simpler sentences: The event is organized for the enjoyment of rich spectators, one of these spectators being Jasper Bagges (Jason Statham), who place bets on who will survive. Bagges bets on his brother Ronald (Ray Winstone), who was brought from the mental institution.