From site: 

Martha is here to help kids learn lots of new words as they play.

Each game on our site introduces a whole bunch of new words. The more kids play, the more words they’ll hear. Play along with them if you can, or talk to them about the games later so they have a chance to practice the new words they’ve learned.

Before you know it, your kids might come to a consensus about which game is their favorite – especially if the weather forecast is for precipitation.

Pick a category to play an interactive game that helps improve your vocabulary skills.  ABC order games give you 10 words to put in order.  Synonym games let you match similar words; antonym games let you match opposite words.

Free Rice combines two goals:

1. Improve core knowledge skills for everyone in dozens of subjects.
2. End world hunger by providing rice to hungry people.

For every vocabulary or spelling word you answer correctly, Free Rice will donate 20 grains of rice to the UN World Food Program.

You set the difficulty level of the vocabulary or spelling words. There are five levels, ranging from easiest to hardest.  Important to note that rice is not taken away if you make a mistake. This is a great activity for English language learners too.

When you register, you can keep track of how much rice you’ve donated. You can also join or start a group that tracks donations made by the group. Great idea for classes or schools!

Free Rice has links to other actions you can take to learn more about and to end world poverty and hunger.

This effort is funded by the advertisers and sponsors of the site.

From site: 

This highly-interactive activity supports critical thinking and problem solving while also building students’ comprehension and spelling skills. Students start by choosing puzzles based on four popular U.S. children’s books. They are then prompted to use clues to identify words from a list of scrambled letters. The final clue is based on an event or theme from their chosen book, which supports story comprehension and makes the activity meaningful and fun. Audible prompts and hints guide students to solve the sometimes challenging word puzzles. After completing a section, students may choose to begin another series of puzzles based on the same book or may choose a different book. This engaging interactive tool would work well with pairs or small groups, either in one session or across multiple sessions.

From site:

A great language activity, “Guess What’s in the Bag” focuses on speaking, listening, and problem-solving skills. Whole-class participation allows students to use their imagination and frees them to play with words as they describe hidden objects, hear clues, and tap prior knowledge.

But this is not only an in-school “exercise”; it is ideal for parents and siblings to play along at home or while traveling. “Guess What’s in the Bag” adds to and reinforces children’s vocabulary as well as their meaning-making skills—learning, and learning through, language.