Proudly made by the TechCraft team, this is a Minecraft style terrain engine programmed in C# in XNA 4.0. Popular Xbox Live Indie Games on Xbox 360 utilized this engine such as Zombie Block Planet, Sunflower Farm and Miner4ever. GunCraft on PC also utilized this engine.
The TechCraft team has a few demos of the engine as they develop found here: Youtube.com
BamYazi also has a video of the experimental WP7 version here: Youtu.be