Try a few of these sites. All free, all good.
kids DO science – Great site sponsored by the University of Georgia, featuring hands-on activities and printable fun and games.
Steve Spangler - Plenty of free activities and videos for all ages.
Hooda Math - Forget the funny name. Better yet, don’t forget it! Nice site with games, movies, tutorials and worksheets aligned to NCTM standards.
PBS Kids - Cool online games, lower level, sorted by subject
Education.com - Fantastic resource for lessons, worksheets, activities and games for all subjects. Searchable by grade level, subject and sub-topic.