That picture is too small to make out any details. Try posting your picture at a hosting site like photobucket or imageshack (both are easy, fast and free) and post the link back here.

It looks like Bishop's Weed (Goutweed) to me. Aegopodium podograria.

Thanks for the information on the hosting site. Here is a link. Let me know if you need a picture of an individual plant.
Thank you so much for your time!

Here is a link that might be useful: {{gwi:1342285}}

I agree with Rhizo_1, Aegopodium podograria.

Nobody's saying anything about how to kill it, a nearly impossible task. I would go for smothering. That might actually be a desirable (temporary) use for landscape fabric. Cardboard wouldn't be strong enough. Overlap well and cover with TONS of heavy mulch, then check to see if it's dead next spring. If it is, you can remove the fabric & return to gardening although I would leave this alone until 2014 to make sure. Good luck!

Thank you everyone for identifying it and thank you purpleinopp for giving us a direction to kill it. Hopefully, someday we can get this under control.
Thanks again!