Apples to Apples: It's a fun party game where there's cards with descriptive words(adjectives) and cards with nouns. Each player gets several adjective cards and you take turns drawing nouns and the rest of the players play one of their adjectives that they feel matches the word played.
Attribute: This is similar to Apples to Apples but each round the person who is leading the round gets to make up the word off the top of their head. Also, instead of everyone trying to play a word that matches the meaning there are cards that everyone has that make it so you're either trying to play a card that matches or that doesn't match the word. So, if the person who leads the round said "Cloud" and you had a card that said "Don't match" you'd play something like "hard" or "rough". Everyone finds a card that works for them and turns it over at the same time, you then all look and choose the word that you think matches best. The trick is if you had a word that didn't match and you got votes, you lose points. If you had a word that didn't match and no one voted for you, you get points. I haven't had a chance to play this yet, but I like the sound of it. It's a little bit Apples to Apples, but also a little more thinking involved too.
Werewolf: AKA Werewolves of Miller's Hollow AKA Mafia AKA Are You A Werewolf AKA Lots of other things
This is a good social game, it's good for about any number of people, no really, it says up to 24 players on Board Game Geek. Everyone in the game is given a role. Those roles let them know that they are either a townsperson or a werewolf. The werewolves know who eachother are and there's also a psychic who secretly knows the identiy of the werewolves. Werewolves want to kill off the townsfolk and the townsfolk want to get rid of the werewolves. Each round of the game the whole room votes on a person that they think is a werewolf and that person is "killed" and no longer part of the game. Don't worry, it's an extremely social game and my friends usually stick around much to our annoyance and constant remarks of "You can't vote, you're dead". And after the person has been killed the werewolves vote and kill off someone, so each round two people are knocked out of the game, it moves pretty quickly. It's good times and can get very loud.
There are a lot of really good games out there, not just party games, I don't know quite what you're looking for, so I'll just say this is just the tiniest taste of things that can be found at www.boardgamegeek.com. Go there and you'll find a ton of games. Oh, I'll also link to the Defective Yeti Good Gift Game Guide, which is specifically a list of games that make good gifts for gateway gamers.