There are two buildings to explore, the first being the Bazaar Hall, where you can try all sorts of local Niigata delicacies (I recommend the sauce katsudon) and do some shopping for souvenirs like rice crackers, sake, or cutlery from Tsubame-Sanjo.
The second building is the Appeal Hall, which is a combination tourism center and history museum. You can find posters and flyers here from all points of interest throughout Niigata prefecture. If you take an elevator up to the top floor, there is a theater and a path that winds back down to the ground floor, taking you on historical tour of Niigata with photographs and hands-on exhibits. There is one area where you can experience falling snow, which is a nice way to cool off in the summer. Also, it's all free!
Attached to the Appeal Hall is a large playground, and right outside of that is a beautiful pond full of carp, which you can feed with a bag of pellets for 100 yen. When the weather is nice, it's a perfect place to enjoy some Yasuda Dairy Farm ice cream.
If you want to make a day of it, I recommend the Shinanogawa Water Shuttle, which travels back and forth between Furusato Village and the Toki Messe building, with a few stops along the way. The ride is scenic and very smooth, and the entire journey takes about 1 hour and costs 1000 yen each way (half price for small children).
Niigata Furusato Village (English website): http://furusatomura.pref.niigata.jp/eng/
Shinanogawa Water Shuttle website: http://www.watershuttle.co.jp/