I made some hula hoops today

for those connectors, file 'em down a bit, then place the hoop ends in a pot of boiling water to soften the plastic. then pop the connectors in with about half the hassle.
I use special glue for the tubing to hold one connector end in place, so I do one end, dry FAST with a paper towel add glue and shove the connector in, than heat the other end.

 

form jasonunbound.com:
How to Make a Collapsible Hoop:

Since I've been getting quite a few requests for collapsible hoop-making instructions lately, here are the basics. In addition to what you need to make a regular hoop, to make a collapsible, you need:

* Four connectors per hoop instead of one
* Bulk bungee cord
* uncoated coat hanger wire
* a power sander (or a lot of patience)
* several pairs of pliers and several hands

Fair warning on two points: First, sanding down the connectors produces plastic dust that you do not want in your eyes or lungs. Wear goggles, do it outside, wear a mask. Second, the final step involves wiring together the two ends of a very taut bungee cord. It ain't easy unless you have some extra hands.

Here's how it works: Measure off a length of tubing to your desired hoop size, and cut. Now make three more cuts, to give you four quarters. Make unique scratch marks across each of the four cuts, so that you know how the pieces should fit back together. Sand the ribs off of one end of each of four connectors. See note above & do this carefully. Sand it partially off, then try to fit it into the tubing. It should offer some resistance, and not be totally loose. Keep sanding all four until the sanded ends can fit snugly into the tubing.

Heat one end of each of the four tubes, and slide the non-sanded ends of the connectors into each, up to the halfway point, leaving the sanded ends sticking out. Using the scratch marks as a guide, fit the hoop together. Prepare an 8 inch long piece of coat hanger wire. Now open the hoop at any of the four points, and snake the bungee cord all the way around until it comes out the other side. Pull both ends, or clamp one end and pull the other. Pull hard. Harder! When it's really stretched (this is what will hold the hoop together when it's really spinning), overlap the two ends of the cord. Wrap the coat hanger wire tightly around & around the overlapped bungee cord. Really dig the wire into the cord. Keep wrapping, and squeeze the wire onto the cord with pliers. When you've got it secured, cut off the ends of the cord.

You should be able to pull the hoop apart with some effort, but when spinning at top speed it should stay together. (If the cord is not tight enough, the hoop will open up when spinning, and pinch you.) The hoop will collapse into four parallel arcs, perfect for traveling.

 

and how about THIS tape?
http://www.identi-tape.com/phosphor.htm

glow in the dark with a 20 year life span?

 

the collapsible is NOT that hard: loop the tubing just like a normal hoop.
add three cuts, so it is in equal quarters.
^
^
^
^ (imagine these are curved)

you need a connector, with one side sanded down, for each joint (4).
set the connectors in on one side (the unsanded one)
loop bungee cord thru the hoop, using the hangar like you'd do a drawstring.
then fasten the cord once it is tight (as that keeps the mid spin explosion from happening. BUT the tension should allow the quarters to be folded together for carrying.
the quarters of the hoop are basically strung like a macaroni necklace.
pop in the sanded down connectors (these are the section points that the hoop will open for collapsing)


pics from hulahoopla.org

I 'd bet that a one half, rather than one quarter fold could work for many applications.