There are many wonderful resources available on the internet that can be used to reinforce knowledge and skills in literacy, numeracy and other subject areas.  Many of these are both entertaining and educational.  A few suggestions are listed below:
 
ABC Splash – Splash is the official education website of our national broadcaster and contains a vast assortment of games and videos to assist students from Kindergarten to Grade 10 - http://splash.abc.net.au/
 
BBC Bitesize -  This site caters to all grades from Kindergarten to senior secondary cross a wide range of subjects -  http://www.bbc.co.uk/bitesize/
 
BBC Skillswise – Designed for adult learners, this site provides basic literacy and numeracy support for older students and others in the community - http://www.bbc.co.uk/skillswise
 
PBS Learning Media – Operated by the Public Broadcasting Service in North America, this site provides resources that are useful for ages ranging from pre-school to high school in Maths, English, Science, Social Science, Health and the Arts.  Although it requires users to sign up, it is free to use and most worthwhile.  - http://www.pbslearningmedia.org/
 
Poissonrouge – This is a great site for young learners that will engage them with interesting activities to increase knowledge and teach basic computer skills. - http://www.poissonrouge.com/
 
 

Please remember that even the most wonderful web sites should be enjoyed in moderation.  It would be great for students to be making good use of sites such as those listed above, but not to the extent where it significantly reduces their physical activity levels.  Place limits on the amount of time spent in front of screens (computers, TV & games) and encourage physical activity.