I want to encourage you to check out FreeRice.com sometime soon.
This site has been around for quite a while (since 2007, I believe), but that doesn't diminish it's importance or value. At it's simplest, it's a question-and-answer game: the website asks you questions, and you select the correct answer from among the ones listed. But here's the kicker: every question you get right donates "10 grains of rice" to help feed the hungry.
The United Nations World Food Programme sponsors the site. FreeRice.com seems to be largely about building awareness of the problem of hunger around the world, as the WFP is funded by donations. The group does tremendous good in the world, and I think this sort of site is a great entry point for conversations with kids about the enormity of the problem of world hunger.
The game was originally set up to be a vocabulary practice game: an English word is listed, and you choose the best meaning of that word. This is still the default mode when you visit the site, but there are many other subject areas you can play as well: multiplication facts, identifying famous paintings, world geography, vocabulary in other languages, and human anatomy, to name a few. (Click the "Subjects" button at the top of the site to select a different topic.)
I'm thinking this might be a good summer review game for kids? Something that will keep them connected to content and reviewing things they've learned...while doing some good in the world at the same time! Maybe set a challenge: donate 1000 grains of rice a day?
I hope you'll take a few minutes to check it out.