-Paper towel tube (cardboard tube)
-Lego's etc. you'll see later
First you will have to buy a mason jar and a light-kit.(Both of these can be found online or at Hobby Lobby. Make sure you buy the correct size light-kit for the size of your jar!)
Next get your paper towel tube and set it next to the mason jar like so. Then cut the tube 1-3 cm below to top of the jar. Remember you can always cut more later so don't cut to much.
Next hot glue or use sticky tack (which is what I'm using) to attach the tube to the bottom of the jar. Skip this step if you do not plan on filling you jar with anything. You can also skip this step if you have a lot of what you need. This is only to reduce the amount of Lego's I needed to use to fill the jar.
Next fill the jar with whatever you want. Here I layered Lego pieces by color but it really does matter what you put in. Another Idea I came up with is layering liquids by density in the jar. If you do liquids then do not use the cardboard tube. The height I filled the Lego's with makes the cardboard tube completely hidden.
Now all you have to do is screw your light-kit put on a lamp shade and screw in the light bulb and your done! Here I'm using a black light with a color choosing remote to make this lamp look five times better.