Infest nooks and crannies with these easy-to-make creeping crawlies.

Paint the Styrofoam balls black and let them dry. Attach the head (smaller ball) to the body (larger ball) with toothpicks.
Insert the pipe cleaner legs into the body and bend them in half to create the knee joints. Bend the tips to create the feet.
Give the spider a frightening face by gluing on two paper triangle eyes.
To make the web, run a length of yarn across the top of a door frame and tape or tack in place. Wet (but don't soak) a dozen or so 6-foot-long strands of yarn and gently pull each strand apart to create a cobweb effect. Drape them over the yarn on the door frame.
Suspend a few spiders on the web by twisting the pipe cleaner legs around the yarn. For maximum chills, invite guests to walk through the doorway, brushing against the wet web as they walk.