Should you come across any unused wine barrel, they can be put to good use. One such use is to use it as a planter box for your out door garden. And here is an example below. The wine barrel is simply sawed into half and after filling with soil, planting can start.
In another example is the wine barrel is saw of at various levels as shown below.
Source: Recycled Wine Barrel Planter
The third example will require a bit of work to rework but the end result of using the wine barrel parts for planting is just amazing. See for your self in the picture below.
Source via: pinterest