I have been looking at other sites with free fun/educational content, so I will add links here to these sites.
Please note: some of these sites may have advertising, so please supervise children's access to them. These links have been checked Dec 2016, and those that no longer work have been removed.
SITES with PUZZLES, GAMES, etc to play or download:
angusj.com/sudoku/ - a free sudoku program to download and install; make and play your own sudoku puzzles in a range of difficulties. I've been using ths program for over a year. It's easy and fun to use.
rinkworks.com/brainfood/ - has a good range of word, logic and number puzzles; also has a free online cryptogram maker.
schoolhousetech.com/ - has free downloads for Basic Facts Worksheet Factory at schoolhousetech.com/Products/BasicFacts/Download.aspx as well as others to try/buy. I have used, and recommend, the Wordsearch Factory (free Lite version)
botproductions.com/conc/conc.html - has an excellent Concentration/Memory game program, with options for playing the games (number of items, sets of picture cards, timer etc) and the option of adding your own card sets. I have made some sets of cards with common sight vocabulary words on them; you can access this game via my memory game page.
wartoft.nu/software/ This has an excellent free downloadable game called Sebran's ABC which has basic spelling and maths games, including a word/picture Memory game; there's also Mini-Sebran for toddlers. The games are attractively presented and very easy to use; excellent freeware! There are also other free programs on the site (geography and language programs).
quiz-tree.com/Sight-Words Sight words lists, free game trial, "Sight Words Buddy".
carlscorner.us.com Lots of excellent games, puzzles and resources to help children learn about all aspects of words.
pbskids.org/ music, games, colouring- simple, fun activities for younger children.
pbskids.org/lions/ Stories, educational games, video clips. Lots of fun...try "Chicken Stacker", a hilarious reading game.
starfall.com/ Appealing animated alphabet activities, reading, etc.
kidsknowit.com/ This site has many different educational activities in a wide range of topics, from animals, dinosaurs and astronomy to math, memory and spelling.
dmoz.org/Kids_and_Teens/Games/ Open Directory Project page with links to many good sites, including:
dmoz.org/Kids_and_Teens/Games/Puzzles_and_Mazes/ -loads of sites to explore!
parenthoodkids.com/index.html -games, recipes, riddles, cards, colouring, as well as parent and autism support
gameskidsplay.net/ Descriptions and rules for dozens of traditional children's games
funandgames.org/ Games, puzzles, activity ideas, humour, quizzes, and lots more- for all ages
topics-mag.com/edition11/games-section.htm -traditional children's games from around the world
mazes.org.uk/ A range of mazes from easy to difficult (and one "impossible" one)
word-searches.com/ Interactive Word Search Puzzles for everyone... Find all hidden words quickly and make it into the Word Search Hall of Fame. Printable Word Search Puzzles also available
greeneclipsesoftware.com/ An excellent, totally free program to download and make your own crosswords... I have used this for the puzzles on my Crosswords page.
varietygames.com/ Free crosswords, wordsearches and crytograms to print, and free trial downloads of programs to make them.
LessonSense.com - free worksheets, crafts and printables excellent printable worksheets, flashcards etc for parents and teachers of primary school children, and also some great games, including Memory Game cards, to download and print. ..Added Mar. 09
janbrett.com -heaps of activities, including games and a free book to print, with delightful woodland animal illustrations..all free! ..Added Mar.09
kizclub.com - brilliant site for teachers and parents with excellent printable educational games, topic and story resources, clipart etc...added Mar 2011
entertainmentcenterspot.com/online-reading-guide-for-kids - thanks to Bethany for finding this site; it has lots of links to good sites to encourage children to read, enjoy and write books, stories and poems! Note: this site has pop-up ads.
(Added Jan. 2012)
commercialofficecleaning.com/tangrams-and-puzzles-for-kids - tangrams are great puzzles to stretch your brain and help you look at things in different ways! Thank you to Dakota for this suggestion :) (Added Dec. 2016)
Oh, and in case you're wondering about the website provider
I use, it's www.webs.com ...
I would recommend them very highly - you can create a basic website for free (if you don't mind some banner ads- unfortunately including dating site ads... or the rates for a Premium, no-ads site are very reasonable if you don't have a lot of content or traffic). The site builder is easy to use for most people; even I have managed to figure it out. Lots of fun!