Alot of us are aware of Microsoft Plus!, which was a enhancement pack with releases for Windows 95, 98 and XP before being discontinued in 2007. These releases were Microsoft Plus! 95, Plus! For Kids, Plus! 98, Plus! Game Pack: Cards and Puzzles, Plus! XP, Plus! Digital Media Edition and Plus! Superpack. Each pack included new desktop themes, games and sound schemes for the operating systems, in addition to a couple of utilizes being included.
However, one Microsoft Plus! product is mysterious in regards to its questionable existence. That was a 4 game pack bundle called "Microsoft Plus! Pack: Four Casual Games. Enhanced for Windows Vista" which was supposedly released in 2008, by Mumbo Jumbo in conjunction with Microsoft. There isn't much info about its existence aside from two English articles on Engadget and Softpedia, and one Italian article by ITavisen.
It's unconfirmed if this Microsoft Plus! pack for Windows Vista was ever released or not, as there isn't any Amazon or eBay listing of this game bundle anywhere.