BLACK I.C.E. is an extensive mod of HOI3 under development by Panzeroo and many other members of the Hearts Of Iron 3 forum.
It works great when it works, but I always after about 15-30 minutes of play. I've lost dozens of hours trying to play this mod, because it really is great, but I literally save the game every 2-3 minutes because I never know when the next crash will happen.