The android free game Crazy Bikers 2 will let you ride your bicycle along extreme tracks. You will have mummies, Eskimos and other strange personalities as your rivals.
You may choose any racer for you and do your best to outrun all your opponents. Make various stunts during the race; it will let you earn money and bonuses. The essence of the gameplay is to take part in races and make mini-tasks. The game world is nicely designed, but not much diversified and you get bored of it very quickly. But it should be mentioned that game physics is perfect.
You will get money for making tasks, tricks and being the first in the races. You will lack the money all the time, as you need it to unlock every new level and every new character. As a result you will have to pass one and the same level once and again or donate real money.