The Cokin Mirage filter will allow you to photograph an ordinary scene and make it appear as if it is being reflected on a large lake. The filter contains a mirrored surface which will reflect a reverse image of whatever your lens points to. By adjusting the angle of the mirror, and with the mirrored surface of the filter facing up, you can achieve the desired degree of reflection you want.
NOTE: In order to use this filter, it is necessary to mount it in the Cokin Modular Hood #A255.