Uh oh! It's a Sedum species. I have several species/varieties gone rampant in my garden. They are actually interesting little succulent plants, but the little "leaves" break off easily and form roots. If you want to control them, I have learned a couple of things - Don't put them in your compost. Don't try and hoe them and rake up the debris! You will just end up with new little ones all over the place. If you use herbicides, Roundup works handily on them. If you don't it gets harder. Personally, I use a Tiger Torch for weeding and I just "boil" the plants which takes care of any bits that break off (please be careful with propane torches). 10% cleaning vinegar sprayed on the might work. Careful hand removal works for me on small corners, if repeated several times. They don't like shade, you can just plant something taller and dense to overshadow them. Or, one can just learn to live with them taking over odd corners of the garden, looking cute and flowering in summer. Plant some different coloured varieties. They do prevent the growth of many even more aggressive species in my area.
Nice variety of Sedum, don't have that one in my succulent garden. Too bad you live so far, I would be glad to get some :) You are probably aware of the dangers of using roundup? See: roundup dangers or roundup toxicity
Sundrop, Oops - It was just a last-resort suggestion. I strongly recommend using mechanical and cultural controls as the first choices, except in extreme cases.
Could be someone is growing it as a ground cover to save him/her-self fertilizing, mowing and watering a conventional grass lawn. As for getting rid of it I prefer old traditional method of pulling out. Great exercise we badly need in the age of TV and computers.
The Live-and-Let-Live solution gets you immeasurably more happiness in the long run, as well as providing you with an excellent mirror of your tolerance. You could use it in conversations, or in nourishing children. Very nice.
