Social City: New 50's diner, playground, and toy store
The 1950's Diner is available for 59 City Bucks, and is the most expensive (but largest) of the three items. The playground is fairly large and can be bought for 48 City Bucks, and appears to be quite popular since it has the least remaining units (under 6,500 as of this writing). The Toy Story is a fun building and is the cheapest at 25 City Bucks.
Remember, these items are rotated out quite often so you'll have to log in soon to buy them if you are interested. You can find them in the newspaper popup that first comes up when you log in to Social City.
Have you bought any of these three buildings? Which is your favorite?