This article is from the web site About.Com: Parenting of Adolescents.  I thought it had some great ideas, so I’m reprinting them here.  And although it’s talking about teens, honestly, these same ideas apply to kids of all ages.

Teens need to know that while summer is great for some down time, it’s never healthy to totally shut down and become lazy. This summer, you should urge your teen to:

Read to learn something new and for fun. Reading serves more than one purpose. While it is good if you can get your teen to read for fun – because reading is its own enjoyable benefit – it’s great if you can get your teen to learn something new through reading. Not only will your teen learn about the topic that he/she has chosen, but he/she will learn how to teach himself/herself something new. This skill will really help your teen when he/she can’t understand what their teacher said in class but still has to take the test. Many teens will give up and do poorly, whereas a teen with this skill has the ability to teach it to himself/herself.

Solve problems. Your teen needs to logically think through problems, such as puzzles, on a regular basis. The critical thinking skills that your teen uses to think through a problem should not be put on the back burner for three months. If you keep this area of your teen’s brain in tip top shape over the summer, he/she will not only be able to handle math class better, but should also be able to make better decisions in all areas of his/her life.

Get some exercise. Teenagers who sit around the house and do nothing but watch TV or play video games are at risk for childhood obesity for one, growing up to be a social misfit for another. Sign your teen up for a summer sports league or get him/her a pool membership and provide a ride back and forth. Teens, not unlike adults, need exercise everyday.