Shrine of Chances are piles of decorative rocks that have a golden symbol floating just above them and they are scattered throughout all the levels
Simply go up to one and push the
button to make an offering to one (everytime you "fail" the offering gets more and more expensive) and hope that you "fail" 3 times in a row for this achievement. If you "win" a certain amount of times, the Shrine will lock up and you won't be able to do anything else with it