glue it to a piece of wood

If you're worried about it flexing glue it to a piece of wood. If you get the right thickness of wood you can match the height of the board to the height of a regular brick (ie: 3 flats high). I've got two of them expoxyed to the center of a 2' x 4' piece of MDF (~ $3 + epoxy) and it works great on the carpet. There's extra room around the plates for building or running cars on, etc.

Oh no, not again...

I needed something to land my Lego Millennium Falcon (check it out at www.amazon.com/exec/obidos/tg/detail/-/B0001CU1HY/ref=cm_aya_asin.title/104-0488135-0118334?%5Fencoding=UTF8&v=glance ) on, so I decided to pick one of these up. It seemed all right at first, but thanks to its lack of rigidity it's a bit loath to hold onto the ship's landing gear. One little flex when I'm movin' it from one room to another, and alla' sudden the Falcon's takin' a catastrophic hyperdrive jump straight downward to Planet Floor. It also doesn't hold onto the various mini-figures very well, either. On the upside: it goes a lot better with those Lego Star Wars ships than the much smaller green base plate I was planning to get instead...

It's not what I remember.....

Yes, it's a grey 15" square Lego plate. But I seem to remember the "baseplates" being the same thinkness as a regular Lego piece. ...the base plate is a thin (1/16"?), flexible Lego baseplate that will allow you to build really big stuff, but it's tough to use on the "living room carpet" because it is so thin it flexes into the carpet when you try to press a "house" onto it. The result is that either only one corner of the house sticks, or it sticks fine, but all the other structures you've put on, flex off.