Budget Traveling Rings/Swing-a-Ring

I've posted before about the awesome Traveling Rings (be sure to check out the video). Here's my low budget garage version:

I have six rings (only three shown). I used these playground rings, 12' NRS straps, and 5/16" stainless steel anchor shackles from Home Depot (for attaching each ring to its strap). A few additional notes:

• As you can see, when the rings are set up for me I have lots of extra strap. But the straps allow me to easily lower the rings for my kids.
• Unless your garage is ridiculously tall (in which case you'd want longer straps), the length of each strap doesn't give you much swinging action, but it's still a good workout, and a nice change from pull-ups. My kingdom for an empty barn with big, high rafters (or any other long, strong, high span these could hang from).
• Note that I don't hang the rings directly from the rafters, but rather from a 2x4 running perpendicular to the rafters. This distributes the weight (my wife noticed some worrisome bowing when I hung them each to its own rafter).
• Ideas: regular hand-over-hand, obviously. Pulling yourself up and staying up while going hand-over-hand is a nice challenge. Or do a pull-up, swing to the next, do another pullup, repeat, etc. is a good workout. Skipping rings, setting them further apart, and setting them at different heights opens up all kinds of options.
• You can't spin like mad like you can with true swiveling components, but the straps can twist. Haven't really done much with that (don't yet have the strength yet to hang from one hand for very long).

Anyway, it's no substitute for the real thing, but still a very fun piece of workout equipment.