ABC for Kids  great site geared to the pre-schooler.  Games; activities and short video clips.  All without  ads!    Try the "Rollercoaster" link for the older children.

Bemboo's Zoo. Simple, clever,  different.  Kids (and grown ups) will get a giggle

Yahoo7 Games heaps of online and downloadable basic games.   But the ads are big and intrusive.

Questacon - the Canberra based science exhibition for children.  This link is to their very cool and interactive optical illusions.

ALFY - site full of games

 A kid safe search engine

Edbydesign    Mainly selling education products but also has educational games and tips on learning to read and write.

  Mini Clip - my kids said I had to put this on the site --just simple clean games, and lots of them.

  Craft for Kids - this site, while for grown-up craft, has a section just for kids.  Kids love nothing more than making their own stuff.

  National Geographic for Kids: pretty good site.  Educational stuff with games and activities. No ads. Geared toward primary aged children.

  YES Magazine - online science magazine.  Don't let that put the kids off, its a pretty good site, but for the mid primary age up.