unusual, out of the ordinary, different, extraordinary, unheard of, unique, rare, few and far between, exceptional, out of the way, strange, exotic, arcane, remarkable, startling, surprising, fantastic, unaccustomed, unfamiliar, anomalous, unclassifiable, freakish, irregular, uncustomary, unconventional, unorthodox, abnormal, peculiar, odd, bizarre, eccentric, original, nondescript, prodigious, fabulous, monstrous, egregious, aberrant, curious, wonderful, unaccountable, unwonted, outré (French), noteworthy, queer, unparalleled, unexampled, outlandish, extreme.
Antonyms common*, usual, ordinary.