OPI Unripened is part of their Halloween launch for 2010. It's an inky blue with sapphire, turquoise and purple sparkles. There is more dimension in the bottle vs. on the nail (the rainbow of shimmer doesn't really translate on the nail like in the bottle), but I find still find it very pretty. It's a lovely, more subtle alternative to all the major, multi-dimensional sparkles that have been popping up lately, (e.g. Orly Cosmic collection).
I purchased this from Transdesign as a large bottle (doesn't seem available now), but it is also a part of the Go Goth! set also distributed for Halloween this year.