Is there some way to make toggle-able spells and abilities? Like for khajiit night-eye race ability instead of casting every 30 sec, just "cast" to turn on night-eye and then "cast" again to turn it off?

It can be done. It requires two spells, however, the first being the ability that you want to turn on and off, the second being a scripted lesser power (cast on self of cource) that turns it on and off. Give the lesser power spell to the player, and in it's script put:

scn YourScriptNameshort DoOnceref CasterBegin ScriptEffectStartset Caster to GetSelfif ( DoOnce == 0 )Caster.AddSpell YourAbillityset DoOnce to 1elseCaster.RemoveSpell YourAbilityset DoOnce to 0End

If you're using OBSE, you can check if the spell is present instead of using DoOnce. Unfortunately, vanilla oblivion doesn't have a function that detects a spell's presence.

the normal script function "isspelltarget" also works like the OBSE "hasspell" function, at least in this situation. I am sure there are some differences, but this works here:

scn YourScriptName

ref caster

begin scripteffectstart
set caster to getself
if caster.isspelltarget YourAbility
caster.addspell YourAbility
else
caster.removespell YourAbility
endif
end