The Meaning of Life, the Universe, and Everything.
A very simple mod to change your gamemode to Adventure mode in certain dimensions. Intended for mapmakers, mostly, though there are probably other uses.
In the config file there's a list. Add Dimension IDs to it.
When you change worlds:
If the dimension is on the list, you are put into Adventure Mode
If the dimension is not on the list, you are put into Survival Mode
If you are in Creative Mode, it ignores you.
That's pretty much all there is to it.
Note that this mod does not add any dimensions itself. It is intended to be used with another mod that does.
(Personally, I'd recommend Mystcraft)
I know the logo is terrible, I threw it together pretty quickly.