This web was made for under $20 and it's entirely woven out of common clothesline style rope. It's about 20 feet high and maybe 12 feet along the base. It's easy to make; it only take a little time. I think it took me about four hours but the results are totally worth it. I've gotten lots of great comments about it.

Step 1: Materials

Only three materials are required.

Rope - I used five 100' lengths. This inexpensive rope is sometimes marked as intended for clotheslines. I cut two of them into 25' lenghts for the perimeter and the three cross ropes. At Walmart the other day I saw 100' lengths of rope for something like $2.64 each. <UPDATE: Harbor Freight sells clothesline for $2.99, item #66565.> If your web is truly humongous (awesome!) you might need more rope.
Rebar - Two 2 foot pieces of 3/8 inch rebar. I got it at Home Depot for under a dollar each. I bent the end into a hook with my vice to make it easier to attach the rope.
Eyebolt - Just a simple eyebolt. The one I had on hand was pretty heavy duty, maybe 4 inches long. I forget what I paid for it at Home Depot years ago but surely it's under $5.

Step 2: Anchor Points

I put one anchor point on my house and two on the ground. You can put your three anchor points anywhere you want but the farther apart they are, the better. For the anchor point on my house I used the eyebolt and attached it under the eave of my roof. I decided to reinforce the location with a scrap piece of wood. I screwed the wood to the under side of the eave and then drilled a pilot hole through both the wood and the eave. I like my pilot holes just a little under sized so I used a big screwdriver to twist the eyebolt in. You'll want this location to be very secure because the ropes we attach later will be pulled very taut. If it should come loose not only would your web be ruined but that eyebolt might become a projectile.

The two anchor points on the ground are done with a two foot piece of rebar in each one. I used rebar this long simply because I didn't want it to come out. I used my vice to put a hook in the end of the rebar. Pound the rebar into the ground at an angle so the rope will be pulling close to perpendicular to the rebar. This will make it much tougher for the rope to pull it out.

Step 3: Perimeter Ropes

If you haven't done so already cut your rope so you have three pieces long enough to go along the three edges of your web. Melt the end of the rope so it doesn't fray. I made mine plenty long so the shape and location can vary from year to year. Any extra rope can be coiled up and stashed in the corners. Start one rope at the top anchor point. Use a bowline knot to secure the rope to the eyebolt so it will be easy to untie later. You'll eventually have three ropes tied to this one anchor so if you don't want to keep climbing back up go ahead and tie all three ropes on now.

Tie two of the ropes to both anchors on the ground using a trucker's hitch. A trucker's hitch is a great knot but it might be hard to understand if you've never seen it tied. The point is to tie a loop in the rope well before the anchor so you can thread the loose end of the rope through the anchor and back through the loop. So you've made a makeshift pulley out of the rope itself. This triples your pulling power and really allows you to make the ropes tight. This is very important to keep the entire web from sagging too much. Go ahead and pull the ropes as tight as you think your anchors can hold.

After tying both ropes from the roof anchor to the ground anchors tie a rope between the two ground anchors. Use the same technique of a bowline on one end and a trucker's hitch on the other.

Step 4: Cross Ropes

Now it's time to add the cross ropes. These are the ropes that the web will be woven on to. Start by tying one of your ropes on to the mid point of one of the perimeter ropes. Unless the triangle made by your three perimeter ropes is equilateral it is likely the rope from the middle of a perimeter rope will not be a right angle when it's tied to the opposite corner. To prevent the cross rope sliding down the perimeter rope I commend a taut line hitch. The taut line hitch resists sliding in one direction only so make sure your knot is oriented correctly. Tie the other end to the opposite corner using the trucker's hitch again but this time don't make it so tight. The tighter you pull it the smaller the area will be that you can use to make your web. Also, it puts even more strain in your anchor points. So use your best judgment to balance the elimination of sag in your web and shrinking surface area.

Do that same thing with another rope from the midpoint of the other perimeter rope . The final rope goes from the roof eyebolt to the midpoint of the rope along the ground. This rope was tied on to the eyebolt with a bowline in a previous step. Use yet another trucker's hitch to secure this rope.

A rundown of every knot used is in the picture for this step.

Step 5: Weave Away

I call this part weaving for lack of a better term; technically it might not be considered weaving. Start dead center where the three cross ropes, well, cross. Tie on by tying three overhand knots around the center in the three possible orientations going around all three ropes each time. It's hard to explain so just tie on in any way that brings the three ropes together. It doesn't really matter; I'm sure it will be fine.

Now start weaving in a spiral out from the center using a clove hitch to tie on to every rope as you spiral around. The beauty of using a clove hitch is that when you take this down you can just take out the cross ropes and all of your (hundreds of) clove hitches will just disappear.

Tying a clove hitch when you have a hundred feet of slack can be troublesome. One trick to help is to coil the rope, wrap a few turns around the bundle and use a carabiner to help hold it together. The carabiner acts as a nice leading point as your weaving and you can clip it to your belt as you pull the slack through. That way you don't have to bend over or get off your ladder to find the end.

The first few clove hitches will take a few minutes but don't get discouraged. Soon you'll be tying them without thinking. There's no getting around the fact that this is a little tedious. Just load up your Ipod with Keith and the Girl (if you're over 18, adult content) and the job will be done in no time. Just be careful not to fall off your ladder laughing.

When my web got to the edges to the right and left there was still plenty of room on the top and bottom. So I kept weaving, back and forth this time, on the top and on the bottom until I decided it was big enough.

When you run out of rope tie on the next one using a double sheet bend. I used three 100' lengths for the weaving part.

I started with the spirals closer together at the center and got farther apart as I made my way toward the edges. It doesn't need to be perfect and symmetrical. Natural spider webs aren't.

Step 6: Spider Etc...

My wife made a spider for the web. It's body and head are styrofoam balls covered with black and red fabric. I attached it will steel wire. It looks pretty good if not a little small. Maybe it's a baby, or the male. HA!

I actually think it's OK without the spider. In fact I think a sign written in blood red paint might be cool. It could say something like...

WARNING
If you don't see the spider then
hide your children and lock
your doors. Because she's
off looking for something to eat.

But my sense of humor is a little... off.

Step 7: Disassembly

The beauty of using a clove hitch to attach the webbing to the cross ropes is that you can simply pull the cross ropes out and every clove hitch will disappear. So just detach your ropes from the anchors, lay it out on the ground, and remove the cross ropes. Then just coil up your rope for next year.

It has been suggested that I leave it together when I take it down so it's easier to put up next year. The reason I don't do this to twofold. First, I don't think it would maintain its shape and look as good the next year. Second, I'm not sure how I would wrap it up and avoid it becoming a hopelessly tangled mess.

EDIT: I tried leaving it together last year and it went up just fine this year. See the next step for details.

That's it. Thanks for reading my Instructable and enjoy freaking out the neighbors with this gigantic web. I've gotten lots of great comments about the web but my favorite is from a girl, maybe 15, who just happened to be walking by as I was taking picture. She said, "Dude! Your web is amazing. You got skills."

Step 8: Putting It Back Up

I tried taking it down without untying the whole thing and it went up... wait for it... without a hitch*. I actually used a couple trucker's hitches on each lower corner to help pull the whole thing taut again. Just be careful folding it up and spreading it out and take your time and it will be fine.

* I kill me