The fake utility box! I first ran into one of these a few years ago and it to date is still on of my favorite finds. It took me 3 returns to finally get it. I have made a few of these myself since then. These are really easy to make and there are many different ways to go about it, so a big part is just choosing what is best for you.
At any local hardware store you are going to want to pick up a small piece of conduit pipe, you can get this in metal or in plastic, in addition you will need to get a out door utility box. For me I like the ones with the little spring doors it makes it easy for the geaocache searcher to get inside. Just attach them together and your in business. You can just put a log book right inside or you can put a smaller container inside the unit like a bison tube.
Now its time to hide it! I find these work well up against hydro poles or street lights, just remember the goldenrule, you cannot deface public property when hiding a cache so you will need to find away to attach it that does not damage what your at attaching it to. Have fun and I’m sure you will get allot of happy geocacher logs who really enjoyed finding your hide.