Sleep is another staple. Arguably, one of the most oft-employed level 1 spells. So... how can you make it weird?
The first and most obvious way is to connect Sleep to dreams and dreaming, perhaps even Dreamworlds?
|Sleep and dream|
- Creatures affected by the Sleep spell see the caster's most recent dream,
- ...or the caster's worst nightmare,
- ...or the caster's sweetest fantasy wet dream.
- Creatures affected by the Sleep spell relive their own most recent dream / worst nightmare / sweetest dream.
- Creatures affected by the Sleep spell enter a dreamworld, unique to the caster. They can act actively for the same amount of turns their corporeal bodies are under the glamour. During this, they can basically wreak havoc inside the caster's mind, emprint themselves into her/his dreams, and so on.
Of course, this last option is a mini-game in itself, and you don't want to waste time doing this every time somebody casts Sleep. But it can be an interesting one-off effect of this staple spell.