Found an awesome tutorial that utilized black paper bags to make seaweed. Which is timely, because I was going to go dig through my fake plant/ivy stores and see what looked the most like seaweed. This stuff actually does look like seaweed. And with relatively little effort. But the best thing about this project is that it can be done bit by bit rather mindlessly while watching a movie or something. So it's a great 'break' project to have.
Basically, you strip the garbage bags into 2" inch strips. I slit the sides (but not the bottom) so that they would be extra long. I folded it up to make it easier to cut through--otherwise, it takes forever, and the lines aren't as even.
Next, you take each strip and stretch the middle out, or pull simultaneously at the sides--either way, you can't really screw this up. You do this all along the strip. I left a little alone at the top of each one in case it needed to tape or tie them together. I'm planning on spraying these with a bit of green paint--possibly a bit of the fluorescent paint so that it'll show up under the black light. I'm also thinking I'll make a bunch--they're a great, cheap, and easy prop to have to cover blank spots, and put in front of wiring to hide it away. And one bag goes a ways--2 bags gave me about 30 strips. Also thinking I'll put a bunch inside, so yeah....garbage bags are going on the grocery list!