The Rogue class at level 2 gain the ability Evasion:
At 2nd level and higher, a rogue can avoid even magical and unusual attacks with great agility. If she makes a successful Reflex saving throw against an attack that normally deals half damage on a successful save, she instead takes no damage. Evasion can be used only if the rogue is wearing light armor or no armor. A helpless rogue does not gain the benefit of evasion.
Does this also apply to spells that have a Reflex save for half damage, such as Fireball?