Fireball pellet discussion brings up an interesting question

[hong]

No. It should not be a Reflex save. It should be a Dexterity check. See DMG p94: "Key Concept 1: Checks are used to accomplish something, while saves are used to avoid something." The Dex check example they give is grabbing someone who is about to fall into a pit.

The check DC should be the spell's DC. "But that can make it impossibly hard to do!" you say. Duh. It should be extremely difficult to leap in front of an entirely magical projectile. Look at Deflect Arrows: DC 20 (granted, a save) for mundane objects. Exceptional DA is even higher.

A DC 20 Ref save is trivial for many mid- to high-level characters (12th level monk or rogue, 24 Dex, +4 cloak of resistance = +19 Ref save). A DC 20 Dex check, however remains hard regardless of level.

This sort of thing looks tailor-made for Epic-level Tumble checks. If someone can wiggle through a wall of force (Escape Artist check, IIRC), I see no reason why they shouldn't be able to block a fireball.