Summer is a great time to learn for fun.  I have listed some great sites for your students to visit. 

www.funbrain.com        Math games

www.starfall.com           primary reading activities

www.arcademicskillbuilders.com          

www.mathplayground.com

www.coolmath.com      variety of math activities

www.spellingcity.com  games to work on spelling words

www.spellingtime.com                                practice with spelling

www.thinkfinity.org      Good overall site for all ages

www.readwritethik.org                               Picture match, word families

www.crickweb.com       Word wheel-beginning & ending sounds

www.dolchword.net     Sight words and matching games

www.primary games.com           English, phonics, science, social studies games and puzzles for primary students