Not long ago. our housemate mentioned that he was looking for good "lunchtime" games that he can play with non-gamers. My first instinct was to grab No Thanks! - it's one of my favorite filler games. It takes about two minutes to learn to play and five minutes to get through.
Here's a short list of good "lunchtime" games that you can play with non-gamers.
No Thanks! - as above. Fast to learn, fast to play. 3-5 players.
Age of War - I've found that calling this game "Strategy Yahtzee" gets the essentials across for most players. Players roll dice trying to get the correct dice combinations to claim cards from the table - including cards controlled by other players! If you can get all of the cards of a single set (all the red cards, all the blue cards, etc.), you lock those cards so that opponents can't steal them and score bonus points. The game ends when all cards have been claimed. If it takes an hour, you're doing it wrong or rolling very poorly. 2-6 players.
We Didn't Playtest This At All - This is the game that Fluxx should be. Fast. Random. Chaotic. And predictable in run time (short). The game lasts until only one player hasn't been eliminated - if it lasts six turns, it's an unusually long game. It also takes about a minute to learn to play. 2+ players (seriously, we've played it with 30 - but most players didn't get a turn ... ). There are also a number of expansions that kick the randomness up a few more notches without slowing the game way down.
Rise of Augustus - Much like Age of War, I can just tell people, "It's strategy BINGO" and go from there. It's a bit more complex than some of the others on this list - call it "5-10 minutes of learning time." And be prepared for occasional questions during its 30 minute play time. 2-6 players.