I went to High School with these two girls father. His mom told me they did not have a computer in their house. They were both very excited to start playing on it. 

• BlockCAD - is a freeware program for building virtual models with Lego-like bricks
• Chicken Invaders - Sometime in the near future, earth is invaded by chickens from another galaxy
• SuperTux - SuperTux is a classic 2D jump'n run arcade sidescroller game.
• Tux Racer - Tux Racer lets you take on the role of Tux the Linux Penguin as he races down steep, snow-covered mountains.
• Scratch - A programming language for everyone. Create interactive stories, games, music and art - and share them online
• Pingus - A journey into the unknown.
• Frozen Bubble - Penguins shooting bubbles, very fun
• US States Game - Memorize the United States Map
• Ri-Li - You drive a toy wood engine in many levels and you must collect all the coaches to win
• Seterra Learn Geography - is a challenging educational geography program with 70 different exercises. Learn about countries, capitals, flags and cities in Africa, Europe, South America, North America, Asia and Australia, using outline map exercises!
• Jessie's Wild West Rodeo - Riding, roping, and barrel racing: Toy Story's Jessie has organized herself a rodeo based on these three indispensable cowpoke skills, and she wants you to saddle up and join the fun. In Jessie's Wild West Rodeo, players become Jessie, riding her trusty steed Bullseye in three competitive events.
• Mulan Animated Storybook - In this series of activities that parallels the animated film, children can take on the role of Mulan in her quest to find the elusive magic scrolls
• ABC Sebran - It is never too early for your child to become familiar with letters and numbers. Sebran's ABC's colorful pictures, pleasant music, and gentle games teach letters, numbers, simple math, and rudiments of reading.