https://yoplait.com/get-your-free-cup
They are giving away one million cups.
Sign up for a coupon for a free cup of Yoplait Original yogurt.
The coupon will be mailed to you.
Update: Here is an additional link for another free cup. You can use the same information you used last time to request this one -
https://www.yoplait.com/products/original/millioncupgiveaway/getyourfreecup_fb.aspx (broken link)
Update #2: Here's yet another link. "Like" them on Facebook, click the calcium tab, click the "Get Your Free Cup" banner, a form will pop up and you can request another. Enjoy!
Yoplait | Facebook