Thunder Valley Motocross Park is not merely the best place to rev your engines around Denver; the 130-acre facility is among the best in the world, which is why it was picked to host the Red Bull FIM Motocross of Nations in September, only the third time the 64-year-old event has ever been held in the United States. Thunder Valley will also host several major events this year, making for the best motocross spectating in the state. And the track is open year-round to local riders Wednesday through Sunday. Start on the kids' track, work up to the intermediate option, then head to the big show to start chasing those trophy dreams.