Ok so I want an ability which increases how high the player can jump. I tried the "jump bonus" with a high magnitude but it didn't seem to do anything. The only thing I found that changes it, is fJumpHeightMin but that is a game setting. Is it possible to set game settings on the fly in a script?

Not as far as I've been able to work out. If there is a way, I'd like to see it also.

I don't believe it is possible using the CK, however I created my own jump mod a while back using TESsnip by modifying fjumpheightmin. I believe the standard jump height value is around 75, so if you wanna be able to jump twice as a high, then set it to 150, and so on....