Wines!D.O. Ribera del Guadiana is the regional appellation of origin, while Vino de la Tierra de Extremadura is another commonly used classification. Ribera del Guadiana has become one of the newest D.O.s in Spain, created on the back of wineries' investment in modern refrigeration equipment to combat extremely high summer temperatures.
This modernising has also meant something of a move from white wines (mainly Viura/Macabeo and the local variety, Pardina) to reds. Whites from Extremadura can be lively and fresh, but are best drunk young. Reds offer the most potential for improvement over the next few vintages.
Rather than producing oxidised imitations of traditional Rioja or under-ripe, supposedly international-style wines, a few of the region's best wineries are now making modern, fruity wines with their own character, Tempranillos which offer extraordinary value for money. Unoaked (Joven) wines are often easy-drinking, while oak-aged (Crianza and Reserva) wines tend to go well with the local pork and cheese. Many of the wineries are based in and around the town of Almendralejo, and it's often possible to visit them if you call ahead. Some even boast an English speaker as they start to focus on export.
A final note - in many rural areas you can find pitarra, theoretically a homemade wine. The real thing is unusual and tasty, but some bars sell an industrialised version that's a fancy name for plonk.