Sora no Otoshimono (Lost Property of the Sky) is a TV anime series based on a "heartful" comedy manga about a fallen - and rather hot looking - angel, erroneously classified as an "unidentified mysterious animal" (UMA) at first. Currently in the works at studio AIC A.S.T.A., the anime will begin airing in Japan from October 2009.
So I hear they're making 14 episodes for this one, but only 13 are deemed "safe" enough for TV broadcast. Nice trick for boosting their DVD sales down the line.