Former northern part of the Kingdom of Hungary, former part of the Habsburg Empire, Austria-Hungary and the various incarnations of Czechoslovakia. Became an independent country on the 1st of January 1993.
Unlike Czechia, Slovakia has historical regions, but no historical lands with semi-autonomous national identities - ergo, it has always been more of a unitary country (if one that was naturally very diverse and a non-independent part of the Hungarian monarchy for most of its history). As with many European countries, the modern administrative divisions of Slovakia don't really mirror the historical ones (or only do so in minor ways).
The eighteenth-century adventurer, soldier of fortune and King of Madagascar Móric Beňovský was born there, although (like Copernicus with Poland/Germany) his ethnic identification is hotly disputed between Poles, Slovaks and Hungarians. Regardless, as any reader of Thande's Look to the West will tell you, Beňovský has enough memetic badassedness for three countries and some more to spare.
Banned ones :
Slovenia - Former Carniola and former Yugoslav member republic of Slovenia. Not to be confused with Slovakia, despite some distant ethno-lingual ties and similarities. And an almost identical flag, too; they really have no excuse for people mixing them up.