@neko nomad,
I may have to write a book: Gardening with Goatheads. They are also known as puncture weeds, puncture vine, mexican sand burrs, and probably many unprintable names. I think our Noddy had a name for them, but I forget what it was.
Some links by others who have encountered the same -
here's a link that suggests using weevils to get them..
http://www.goatheads.com/
that site also has ads for weed burners (a new one on me) and doggie paw mittens..
and a link to goathead apparel. Good grief..
so now I know the latin name, and won't forget it - Tribulus terrestris
http://cms.jcu.edu.au/discovernature/weedscommon/JCUDEV_012578
Hmmm, good name for a dog...
Now here's a matter of amazement to me - apparently they have some kind of health benefit - see the google ads to the side of the sane blog poster's piece on goatheads -
http://www.friday.com/bbum/2007/07/07/tribulus-terrestris-goatshead-terribly-evil-plant-from-hell/
I somehow misplaced my leather gardening gloves. Had to buy a new pair yesterday...