One of the things you really can't miss out on when in Bali, is walking through the famous Tegalalang Ricefields. Just outside Ubud you will find this breathtaking view over the green rice terraces of Tegalalang. You can walk on a small path that will lead you through and will see the local farmers busy on the land.
It's quite a popular spot with tourists, so our tip is to go here really early morning and avoid the crowds. It's also nice because it's still cool and later in the day it's too hot to take the walk.