Rock of Ages

The game combines tower defense strategy with a rolling ball mechanic similar to games such as Marble Madness and Super Monkey Ball. The aim of the game is to use a large stone boulder to attack the enemy's castle at the bottom of the hill, whilst using various defensive structures to defend your own. Players can use a variety of obstacles to defend the path leading up to the castle, such as buildings, dynamite, windmills and animals. Source: Wikipedia, "Rock of Ages (video game)", available under the CC-BY-SA License.