If you have moss growing in some part of your yard, you might want to start a moss garden there.
Start by marking off the area with a spade in the shape you want. This entire area must be in the shade all day. Level the area with a hoe and remove any weeds, roots and all. The best way to do this is to pull them by hand. You can wet the area first to help loosen the weed roots.
Moss needs an acid soil with pour drainage. It also needs constant shade.
Dig up moss, with roots and soil attached, from your yard or purchase from a plant nursery. Mix moss, dirt and all, with 1 cup stale beer and 1 cup buttermilk. Mix in a blender until liquified. Pour over prepared area until completely covered. Keep moist by misting several times a day until moss starts to grow. Then mist about once a week.
To get moss to grow on the sides of clay pots or on stone or brick walls, spray mixture on surface and treat as above, misting several times a day until moss begins to grow. Be sure to keep the containers out of the sunlight.
Idea from Paul James of Gardening By the Yard on HGTV.