Carcassonne helped change my expectations of what a good tabletop game should be; less focus on dice rolls and more on skill and planning. The only random aspect comes from the order in which tiles are drawn from the available pool. Players then place them on the table touching matching features of tiles together, to complete landmarks and score points.
The game is easy for any ages to learn; average time bringing a new player up to speed with the rules is less than a half-hour, about the length of one game. The game is evenly-matched between all players at all times, and besides a better grasp of some of the more complex scoring rules, veteran players don't have much advantage over novices.
I haven't had much experience with the game's numerous expansions, but even vanilla Carcassonne presents players with enough variety to support numerous play styles and preferences. This is definitely something anyone planning a game night should pick up.