Zentangles are surprisingly very easy to do and require very little in the way of supplies: just a Micron Pigma pen (I use a set of 3 with .25 .35 & .45 tips) and some smooth paper. There are no rules, you can do them anywhere, and you are only limited by your imagination when it comes to creating the "fill-ins"--i.e., the lines, squiggles, dots, etc. that you use to fill in the spaces. Really, any dumb little mark looks fabulous when repeated in an organized manner.
"Yeah, but what can you actually do with them?" you ask.
Well, they are, of course, suitable for framing. Centered in a large frame under a wide, over-sized mat, they would make a stunning piece of abstract art for your wall.
Or, here is another idea: scan them into your computer and print them out onto that Shrinky Dink plastic specially made for use in inkjet printers. You can use markers to color the edges to give it some pop. Then shrink in your oven til it lies flat. Add some jump rings, a few beads (Oh! don't forget to punch any holes before you bake it), and a pin back and....
Now I ask you, just how artsy-fartsy chic are these?