Samloyal23
Adventurer
Flame Breath, shout, ventriloquism and a plethora of other vocalised spells could be used with this feat if you are gagged or otherwise muted. That said, what other strange feats have you seen?
The strangest I've seen in a WotC book is Blessed By Tem-Et-Nu from Sandstorm (for 3.5). It's essentially a hippopotamus-themed feat, including the ability to command and rebuke hippos as an evil cleric commands undead, and the prerequisite "must have defeated a hippopotamus in single combat."