Best Free Online Applications and Services: Games

Chess

Little ChessPartner, as hosted at Chess.com, gives you a lively game against your computer in a friendly interface with adjustable settings.

All in One Place

Friv, "a full-screen of tiny screen shots for more than 250 free online PC games of various genres with the most popular ones in hand from time to time, just in one place."

Match-3 Puzzle

Cradle of Rome, "a thrilling path to puzzle glory. Build the heart of the Ancient Roman Empire by playing and conquering more than 100 addictive and intuitively designed levels."

Jigsaw Puzzle and Creator

Jigsaw Puzzle Gallery at JigZone, "choose a puzzle from a gallery of beautiful pictures of animals, art, flowers, scenes and other categories, change cuts into 6 to 247 pieces in different shapes.

Jigsaw Planet, "create your own puzzles with difficulty levels, shapes and rotations, play your own or common puzzles or even send puzzles to friends."

Game of Go

361points.com, "you can play against the GnuGo engine online with three different table sizes to choose from and engine strength is adjustable. A big bonus for beginners is the chance to challenge an online computer to play a simplified version of the game called Capture Go."

Tetris

Tetris N-Blox lets you play the game up to 10 levels of difficulty with colorful shapes, optional full-screen mode and sound effects in a simple design. It's easy to play—just click the game logo and start a game.

Sudoku

DKM Sudoku Online, "almost as fully-featured as any of Sudoku download. Click Play Now and go to Menu to create a new puzzle in any of 4 levels. You can enter possible cell values manually in pencil mode, or let it scan for you."

Reversi Lounge "lets you select a server from the list, clickLaunch button to open the lobby screen, select an empty chair at one of the tables and play online free against the human players in the lobby."
Othello Game, "a good choice to challenge the computer opponent with 3 levels of strength, undo moves, highlight valid moves, hints and animation effects."

Backgammon

Motif lets you play backgammon against a decent computer engine via a functional 2D interface. Good documentation too.

Games for Charity

FreeRice, "play educational quiz games to help fight hunger around the world, each answer you get correct contributes 10 grains of rice to WFP, the best of its kind I have seen so far."