You can learn spells just by seeing them cast.
Prerequisites: Ability to cast arcane spells, Spellcraft 1 rank, Intelligence 15
Benefit: If you beat the DC to identify a spell being cast by 10, you can use a memory-aiding mnemonic to act as though you had a scroll of that spell for the purposes of scribing a new spell into your spellbook or adding spells to your familiar. This mnemonic lasts for 8 hours, after which you forget the precise look of the components. Due to the need for experimentation, scribing these spells costs an additional 25 gp/spell level worth of materials.
A fun feat for wizards and the occasional witch, which can let them use the enemy’s magic against them. It’s always more interesting when your character’s major actions–like learning new spells–happens on-screen, so to speak. You can watch your character increase his or her knowledge, and feel good for once about putting all those ranks into spellcraft. It also means that identifying spells being cast during combat isn’t a waste of time. You will actually care whether or not you succeed.
Have fun with this one!