buildzion.com

Blokus     (4 players)
Bookworm    (like Boggle)
TextTwist 2    

Blokus is a classic board game for up to four players in which you place your pieces corner-to-corner, but you can't touch the sides of your own color. Whoever puts down the most pieces wins. Good for all ages. About 7$, and there is a coupon code: RETAIL20

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

This is the classic 2-player game, Tron, where you try to entrap the other person with the line you draw!
Very fun for father-son competition!

  Author's site: wtron.sourceforge.net

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/

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  
Installer

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

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, 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

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

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 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

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 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 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

Nadeo.com has the best free car racing game trackmanianations.com and virtualskipper.com for sailboat racing. And for a flight simulator: flightgear.org and for the space shuttle: orbitersimulator.com

This is Tic-Tac-Toe with a twist: only 3 of your moves can be in use at any given time--as soon as you place your fourth move, your first move disappears! For 1 or 2 players--surprisingly fun with a younger player!

Author's site:  sourceforge.net/projects/tryx