Synonyms for Oddity (same or very similar meaning)
WordNet sense 1 (eccentricity that is not easily explained):
oddnessWordNet sense 2 (a strange attitude or habit):
crotchet, queerness, quirk, quirkinessWordNet sense 3 (something unusual -- perhaps worthy of collecting):
curio, curiosity, oddment, peculiarity, rarityFrom the ODE community, based on WordNetadd/edit