[This post repeats a contribution I made to the Usenet news group, triangle.dining in August, 2007.]
I chanced upon these fruits at Kroger last week, bought one, and let it ripen.
Bit into it, and was rewarded with a super-sweet juicy flesh much like a plum. No sourness or bitterness. Tender skin. Gorgeous flame-red flesh. I don't recall the variety but it looked like "Flavor Supreme".
Googling pluot (pronounced plue-ott) I learned it is a complex hybrid patented in 1989 by Floyd Zaiger said to be the modern Luther Burbank of stone fruits. Two-thirds plum (the plu-), one-third apricot (the -ot) (but I couldn't detect any apricot quality. There are more than a dozen cultivars.
Try 'em, you will love 'em. Harris-Teeter is offering 4 varieties this week at $2/lb.
Read more at Wiki:
http://en.wikipedia.org/wiki/Pluot