We can't BELIEVE this stuff works, but, from all the reports, it's apparently outstanding.  There's a company called Still Spirits that transforms your vodka into other types of liquors.  At least, it transforms the taste.  But isn't that good enough?  The company sells little bottles that you pour into your vodka to change the taste.

They analyzed Jack Daniel's bourbon, Bombay Sapphire gin, Bailey's Irish Cream, Bushmills whiskey, Bacardi rum, and several other liquors to figure out the key ingredients that give them their taste.  Their bottles replicate those ingredients.

This really doesn't sound like it should be any good, but online reviewers swear by this stuff.  You can flavor a full bottle of vodka with one of these, they cost around $6 or $7 online. 

(Gizmodo)