In general, any effect that allows you to gain temporary hit
points over time allows you to stack those points...
D-Man said:Can say a 10th level cleric or paladin burn three turn attempts in consecutive rounds and get 60 temporary hp and +30' movement?
Thanee said:And no, they do not overlap either (as in, once the first are gone, the next are used), that would be the same as stacking.
Scharlata said:If we have Argos the Threefold-Blind, a 5th level cleric, who just activated his feat Divine Vigor and gained 10 temporary hit points and gets in a fight with a Bone Creature Wizard that casts a Lightning Bolt at him thereby blasting his temporary (and some of his normal) hit points away, allowing our hero to re-activate his feat again next round to get another dose of the juicy 10 hit points.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.