Bangai-o Spirits for the DS is coming out in the US soon. Not only do you get a sweet Treasure shooter (same dudes who did Ikaruga, so prepare to either die a lot or get enough blood transfusions from tiny Asians until your reflexes improve sufficiently) and a comprehensive level editor, but you can share levels you make with anyone. (Well, anyone who has a DS and a copy of the game)
I won't spoil the surprise, but I'll say that it doesn't use the existing DS wireless infrastructure. Kotaku has
the story about the magics performed by these sorcerers from across the seas.