I think a level set in a modern giant's town would be awesome. You could have areas set in a shopping mall, family home, or even a senior citizens club!
![smilie](http://forum.darkspyro.net/images/xd.png)
I would also like a musical themed environment in some shape or form.
A two player mini-game for the giant area could be where both players are inside a giant trolley, hurtling down a hill. One player steers and collects helpful items, while the other fends off attacking enemies. The player steering has a weak attack for back-up.