Yes, I'm doing Zentangle, sort of. Here's my first "keeper" design:
I trashed several first attempts before I got to this one. Good thing I'm working digitally! I used my PSP Pro software, because I'm too impatient to fool with paper & pens, and I needed the practice with PSP's drawing tools. I really couldn't grasp this Zentangle stuff just by working in black & white - It was only when I turned to color that I could let loose. I started the color layer first, then did the trace, and then filled in the areas with the black. Then I went back to the color layer and added more colored-penciling to bring out the design. Works great for me when I do it that way (my way!).