I recently bought a spindle of 10 Commodore DVD+Rs (for £6), only to find out that they don't work with my DVD burner (a Pioneer DVR-107D). Well, they half work; it can write them perfectly well, just that it can't read anything off them afterwards, and nor can my iBook. (Oddly enough, the Pioneer drive has no problems with other DVD+R media, including Verbatim.)
So now I have a spindle of 8 unused Commodore-brand DVD+Rs which are of no use whatsoever to me.