buildzion.com

This is one of the best 2-player games--better than Tetris! Rotate colored spheres to line them up in groups of four. You will drop a blockade on your opponent by getting multiple combinations. 

This is an edited version for buildzion.com (GPL license)

Author's website: http://www.ios-software.com/?page=projet&quoi=29

A family night classic with up to 4 players at once! Try to paint the screen with your color of paint by moving your paintbrush around the screen. Whoever has the most painted when time runs out is the winner! Surprisingly fun as you paint your opponents' tracks!

Author's website:  http://www.jjsoftgames.com/english/battlepainters/

This is a fun game for whole family, with up to 4 racers at once. You have to click "settings" first to set up the keyboard for the additional players. You can choose from 3 cars and 3 tracks (by typing enter for the selections).

Author:  http://frcadev.tym.cz/multiracer

The best free 1 or 2 player Tetris on the internet! 3-D graphics adds an impressive look. For the two-player option, use "Splitscreen". Swiftblocks is also a good 2-player version.

 
Source: www.caiman.us

This is a popular game for 2 players! Swap pairs of blocks horizontally to form groups of 3, erasing them, before they reach the ceiling! It is a remake of Tetris Attack.

Source:  blockattack.sourceforge.net

Bookworm is the classic word game like Boggle in which new tiles appear after a word is found! Rocket Mania and Talismania rotate pieces to connect a pipeline to get to a target. Gutterball is bowling, and HamsterBall is a game like Marble Madness.
Bookworm Deluxe
Rocket Mania
Talismania
Gutterball2
HamsterBall

The online versions are free, but the full version can be purchased for 7$ (one per month) at Gamehouse.com.

The best freeware racing game on the internet! Race down the mountain to collect fish before time runs out!

Source: tuxracer.sourceforge.net

This is a fun, fast version of the classic ball-and-paddle game, especially good for younger players to learn some quick reflexes. It's a high-quality game considering it is free!

Author's site:  interq.or.jp/tohoku/kenta/e/download/block/block.htm

For some reason, children just love this game! The objective is easy: roll you marble around to collect stars in 3D graphics! If this link ever breaks, please contact me.

Download Page
(for Mac, too)

Source: www.marble-arena.com

This game is a must-have for any family! Solve the classic puzzle-game by solving the correct order of colors -- sounds easy, right? A white dot means "there is a right color in the right place" and a black dot signifies "there is a right color in a wrong place". Absolutely fabulous!

Author's website: http://web.telia.com/~u43509647/

In this game, young children place different shapes within a certain space to fill it completely. There may be more than one "right answer". This is an excellent, high quailty game by Mike Archer.  

Author's website:  www.mikearcher.org.uk

Similar to Sokoban, try to push the blocks onto their targets within an enclosed room with walls. You have to push with advanced planning to reach your goal.

Author's website: www.mikearcher.org.uk

A good one for children with high-quality graphics. Single-player only. Aim around the mini-golf course obstacles to earn the lowest-possible score. A great game.

Author's website: http://www.krunchopia.com/?page=mrputts

This is a fun collaborative game in which several children at once can look for squares hidden within the mixture of game pieces. Find the biggest square you can while time is ticking away!

gamemakergames.com/?a=view&id=873

This is a classic game for younger children! Aim your ball to connect 3 of the same color before the descending balls cross the line!

 
Source: djes.free.fr

Although hard to learn at first, this might be one of your favorites. It's a two-player race to move the marbles into group of 3 in the middle row! Sounds easy, but it can be a challenge.

Source: millstone.demon.co.uk

This game is a long-standing worldwide classic -- just turn over the tiles to sandwich your opponent's colors. Whoever has the most with his or her color on the board at the end of the game is the winner.

Author's website: http://www.sos-software.co.uk/freebies/othello/othello.html

Author's site: pessimization.com/software/jools/

The best 4-in-a-row freeware game on the internet is iPuissance 4D. This version even comes with 2-player options and also a "special rules" game variation. A competitive time-tested family classic game: just drop your checkers in the grid to line up four in a row in any direction!

Author's website: ipuissance4d.beroux.com

This is a fun puzzler that younger children love -- place arrows on the screen to give directions to the Chouffies. If you can solve the puzzle by leading them to the destination, you pass the level. It is writtin in French, so Retirer means remove and use the space bar to start.

 
Source:  www.caiman.us

This is a fun puzzle game with the objective of moving colored blocks in a rectangular path in order to obtain a pre-determined pattern. Very intriguing and worth the download. It was highly-ranked in a freeware game competition.

 
source: ishisoft.com

 The best free Mah Jongg classic matching tile game on the web! Thanks to Reto Schoelly!

 
Source: reto-schoelly.de

Snake allows for up to 4 simultaneous players as you steer to avoid collision while trying to eat the apple! A popular game among youngsters.  Controls: arrows, WASD, IJKL, 5123.

Author's site: snake2.com

This puzzle game is an enjoyable way to spend an afternoon. Move the ball to the target by choosing a path through a room with walls. It is similar to tilting the bottom of the game board, but you can move the items individually.

Author's site: stephane.mitermite.free.fr

This is the classic card-matching game with up to 4 players. This was the best of its class when I tested, but unfortunately, the author's site is now down. Especially good for young players!

Author's site: customfamilygames.com 

This is a game of angles, primarily designed for younger children. In this game you bounce the ball to the target by changing the deflector angles.

Alternate site: demonews.com