Biome Ambience is a small and simple mod,
that allows you to change grass, foliage, temperatures, music and ambience of every single biome including modded!
Installation
Just drop BiomeAmbience-1.0.0.jar into the "mods" folder.
If you are playing on a server, you can install BiomeAmbience only on your client.
(but if you forget it putting this mod in the server "mods" folder, nothing bad will happen!)
And the API is simple too!