Small for big has a Halloween project making spider webs out of beige yarn, sticks and plastic spider rings.
Good for ages 5 and up.
Get the instructions here:
http://smallforbig.com/2012/10/halloween-diy-yarn-sticks-spider-webs.html
Craft berry bush creates a spider web ball, gluing yarn to a balloon and popping it once it dries.
Get the instructions here:
http://www.craftberrybush.com/2011/09/itsi-bitsi-spiders.html
Craft elf uses fluffy white yarn and popsicle sticks.
Get the instructions here:
Happy hour projects uses popsicle sticks and a thinner yarn.
Get the instructions here:
Oh happyday makes yarn spider webs without sticks and puts them on trees and bushes.
Get the instructions here:
Alanna george uses pipe cleaners instead of sticks for her version giving it a fuzzy tarantula effect.
Get the instructions here:
Crafts by amanda adds a pipe cleaner spider.
Get the instructions here:
Grinning like an idiot uses glow in the dark spray.
Get the instructions here:
Little pink monster uses glow spray as well.
Get the instructions here:
Better homes and gardens uses black yarn and orange spiders.
Get the instructions here: