Thematic Games contain a strong theme which drives the overall game experience, creating a dramatic story ("narrative") similar to a book or action movie. Some well-known examples are Battlestar Galactica, Twilight Imperium and War of the Ring.
This type of game often features player to player direct conflict (with the chance of elimination), dice rolling, and plastic miniatures.
A Thematic Game is usually created around its main dramatic theme, which its rules and mechanics aim to depict. Themes typically involve fighting or good-versus-evil conflicts with heroes and villains. Science fiction and fantasy themes are common.
This is contrasted with Strategy Games, also known as "Eurogames." Eurogames are usually built around an elegant set of mechanics, with a more general theme (e.g. Power Grid or Agricola). Themes tend to invoke more everyday events such as trading and building.
Thematic Games are sometimes called Experience Games or "Ameritrash" games (meaning "American-style boardgames"). The latter name can be controversial, but is generally embraced by long-time lovers of the genre and is not considered derogatory.