Ever see those neat landscaping lights that light up your tree at night but stay hidden in the day acting like rocks? Ever notice how the store bought ones look fake? Plastic rocks are hard to make look like real rocks, and even if you find one that looks like a real rock, does it look like the other rocks in your garden? Probably not, and you just paid $20 to $50 to have a plastic rock in your garden. We can do far better for far cheaper.
The heart of this build is an incredibly inexpensive LED light. This light, while made for cars, works great in landscaping lights as they both run on 12v DC. These lights are "outdoor" lights in the sense they are exposed to the elements when installed on a car, they are reversing lights...buck-fifty reversing lights. Outdoor-worthy, cheap, bright and have a long pre-wired tail to make the install easy.
Next we find a stone, one that matches the other stones in the garden, something that will look natural not all plastic and fake.
Pick the ugly side, if there is one, and drill a hole through it. Make sure to pick a spot that will be thin enough for your drill bit to reach the other side. Also, unless you are drilling a very soft stone, like sandstone or lava rock, you will need to use a hammer drill. If you've never used a hammer drill before, don't be intimidated. A hammer drill simply works like a normal drill but rapidly vibrates the drill bit to drill into hard surfaces like concrete or stone. Using either type of drill, make sure to use a masonary bit. Bits made for metal or wood will likely be heavily damaged using them this way.
After you have the hole drilled, you will need to open one end up wide enough to fit the head of the light in. I used a larger masonary bit but you can just wobble the drill while drilling or chip it away with a hammer and chisel if you want.
Once you have the pocket drilled just thread the wire from the light through hole and out the bottom of the rock.
Pulling the light in tight and you can see how innocuous this little light is. At this point, you could use some silicon to hold the light in place or just leave it loose in the hole like I did so it can be changed out easily in case of damage.
Your rock is now complete, simply wire it into your existing landscape lights and snug it up to a tree, bush or wall to add some nighttime character to your garden. Make sure you test the polarity of the connection as LED lights, unlike regular incandescent landscape lights, care which wire is positive and which is negative.
Very inexpensive, very easy, very bright and very cool!