Puzzles and multiplayer rooms
Wikipedia has an entire entry on the mathematics behind Planarity, but you don't have to be a math geek to enjoy this puzzle game. Basically, it presents you with several points connected by straight lines; your goal is to reposition the points (which drag their connected lines in rubber-band fashion) so that none of the lines cross.
Planarity seems fairly straightforward when you start out with just six points. But the number of points and lines escalate with each level, and you'll spend quite a bit of time figuring out the puzzle as they climb higher into double digits.
Brettspielwelt means Board Game World in German, and this totally free (and ad-free) site is all about recreating board games online for real humans to play. Don't go looking here for Monopoly or Clue, however; the games are generally less commercial and more contemporary. Popular titles include Settlers of Catan, Carcassonne, backgammon, and the Asian classic, Go.
Brettspielwelt demands a certain amount of effort for newcomers. While you can play directly in a browser, things may go more smoothly if you download and install a Java client. Although by default everything is in German, you can tweak the settings to default to English (detailed instructions for doing this can be found on a Brettspielwelt tutorial website devoted to helping English speakers get up and running).
While most of the players are German, they almost all speak at least some English - and there is a large contingent of native English speakers.
The games can be complicated, too - it's not easy to recreate three-dimensional game pieces and game boards for a two-dimensional PC display. But the graphics are pretty amazing, and if you find a board game you love (there's a list of the games on the Brettspielwelt site; click the small British flag on the upper right to get the English version), you'll love being able to play it online pretty much 24 hours a day - for free.
Have you ever played Pictionary? ISketch is a surprisingly sophisticated (and totally ad-free) Shockwave version of the game, where a group of players try to guess a word or phrase that one of them draws. The game randomly assigns sketching duties (ten rounds per game), and you know it's your turn when a set of drawing tools (simplified versions of palettes found in all image editors) appears, along with the word or phrase you're supposed to draw. You're awarded points for guessing the word that's being drawn (the person who gets it first receives the most points), and you also acquire points when people successfully figure out what word you're drawing.
Game play goes on in dozens of rooms that each accommodates up to ten players. There are rooms for different languages, and for specialty subjects such as movies or songs. Users are invited to submit their own word lists (at least 1500 entries are required) to form the basis of a new room.
The rooms have one pane for drawing, one for typing in your guesses, and another for chatting, where nothing you type is construed as a guess. Players police each other; people who persist in rude behaviour, or who scribble words in the drawing pane, are often given the boot.
I stumbled across ISketch several years ago and was amazed by it then; I'm positively stunned that it's still running as a free game with not a smidge of advertising (as opposed to Shockwave.com's similar InkLink game) - and with even more features than I remembered. It's a true Internet gem.
Still more on tap
This isn't so much a site for online games as it is a site for downloading and playing big PC games - commercial titles, some of them older (BloodRayne, Bust-a-Move, Myst, Root Beer Tapper), that you once had to purchase on CD or DVD.
To begin using the site, you must first register and download a player app that allows GameTap to dictate the rights associated with its titles - for example, I will only be able to play the original version of Myst (called realMyst here) for free until December 31. GameTap changes the free game lineup every week, and when I visited the site recently, it indicated that only 44 of the nearly 1000 games in its catalogue were actually free.
The game downloads can be huge - several hundred megabytes. Still, some are vintage A-list titles that people may enjoy revisiting - especially for free.
BoxerJam is not the most attractive site on the web, and it can be a bit pushy about trying to get you to click on ads. But it has an entertaining collection of word and puzzle pastimes - and what really keeps me coming back are a couple of highly addictive multiplayer game-show-style games.
In Strike a Match, you're presented with a collection of six or nine names or phrases (depending on the round of the game) from which you must click the two or three (respectively) that belong together. You play against up to seven opponents (although many tend to drop out as it becomes clear that they aren't doing well).
I also like Out of Order, in which you compete against other players to successfully unscramble words before the clock stops. (The game doesn't make you type in complete words - it demands only the first three letters, and if you get those right it assumes you know the rest.)
Speaking of game shows, our last site presents a novel approach to gaming. Moola lets you compete (for free) against other players to win cash prizes funded by ad dollars. It works like this: You start out with a penny that Moola gives to you, and you try to double it by playing a game against another player who also has only 1 cent. The winner plays against someone else with 2 cents, and the stakes keep doubling as you advance; if you lose, you start over again with another penny.
Caveats: Participation is by invitation only (remember the early days of Gmail?), but you can ask to be invited; it took me all of 15 minutes to get an invitation. Also, you don't have much of a choice of games; only three (two card-like games and a version of Rock, Paper, Scissors) at the time of writing. But the site's literature says it will be adding more games, and the prospect of winning millions (however remote, as you would have to win a whole bunch of games) does give game play an added dimension.