Heat Rush is a great Flash racing game which looks a bit like the original Cruizin' USA arcade game. The gameplay is balanced well with tight turning control, power boost (nitro), and fair car-to-car collision physics. Various in-game upgrades can be unlocked with racing achievements.
Nice looking cars rendered from multiple angles add to the faux-3D environment which includes realistic turns as well as hills. Several different tracks to race on feature custom backgrounds and road-side obstacles. Your best time for each track is saved automatically which can be submitted for hi-scores.