"Codenames" is a clever word game. It has a downside that it requires at least 4 players. There is a board of words (each word is on a double-sided card and there are a few hudreds). One person on each team has a diagram with certain words (array indices) he must communicate to another team members. He does that by saying a word (word association) and a number, which means how many words he's communicating. For example, if there's a ring, a journey, and a monster you could say "Hobbit 3". Unlike a similar game, Dixit, this one has better longevity as it doesn't promote saying very obscure things only one person in group will know.
Neuroshima Hex! is a bit nerdy looking, but it's simple without expansions. Retro apocalyptic setting with mutants and evil robots. A knife fight in a telephone booth, plays well up to 4 players. You fill up the hexagonal board with your troops (they mostly don't move) rotating them so that they will hit the most enemies. Then it either fills up completely or one of players plays Battle token, and everything goes off like a chain reaction. Units hit in melee or shoot in order of their initiative. High interaction, tight mechanics. Most people prefer it as a duel game though. You can play it online too.
Neuroshima Hex! is a bit nerdy looking, but it's simple without expansions. Retro apocalyptic setting with mutants and evil robots. A knife fight in a telephone booth, plays well up to 4 players. You fill up the hexagonal board with your troops (they mostly don't move) rotating them so that they will hit the most enemies. Then it either fills up completely or one of players plays Battle token, and everything goes off like a chain reaction. Units hit in melee or shoot in order of their initiative. High interaction, tight mechanics. Most people prefer it as a duel game though. You can play it online too.