The new IKEA catalog includes this reminder that there are now just 52 shopping days left until Park(ing) Day 2013 on 20 September. Having documented a few similar installations in the past, I’ll say that the practiced tiny-room-builders get these elements right:

• Floor: define the horizontal space with “symbolic groundcover.” A large green rug is great because it’s relatively light and quickly rolled out, but for reuse purposes, keep in mind that it might get dirty. I tried hauling remnant sod to our site, but it turns out that live plants are terribly heavy. Even lighter-weight: chalk!
• Walls 1: stake out the corners with vertical elements. Not necessarily as high as the fabric screens shown, but enough to…
• Walls 2: structure the space so that the “backs” face cars and the “front” faces the sidewalk. They could have done a better job with sheltering the street face of this one, but that would’ve blocked the camera’s view in.
• Ceiling: define the space above with a shading element; the umbrella shown is again a very lightweight answer.
• Weight: A temporary installation should be literally lightweight and easy to pack in & pack out — particularly if you’re committed to a car-free Park(ing).

That said, it’ll cost more than $320 to furnish a Park(ing) Space at IKEA: a typical American parallel parking space is 9′ x 20′: large enough for four of those HAMPEN rugs, laid perpendicular to the curb, not just one laid parallel. Also, this seems like a great chance to show off some of their outdoor collection: a potted tree on a plant stand, for instance.

More resources: the official Park(ing) Day Manual, plenty of photos, and even more Flickr photos.