Day & night cycles would be a big +5 for me. Infravision, hide in shadows, burglary adventures (ref. Narlen Darkwalk), undead encounters, light /darkness spells, Ring of Shooting Stars, SpongeBob burning his hand on the grill, etc. all have day/night aspects and mood elements. And when we finally get to the City of Brass, it would be great to sneak around in the dark!