My new favorite activity to do with my students is What am I? I have my students create questions that end with "What am I?"
Example - In reading, with our word wall words, students have to write clues for the words. If the word was baseball, they may write
1. This word is a compound word.
2. The first word is something that you can put dirty clothes into.
3. The second word word is a synonym of sphere.
What am I?
My students enjoy this and it works on thinking through all the possible clues that they must give. It helps develop their writing as well. Some students like to vary this activity on their own by coming up with sentences that force those guessing to use their context clues.
As a variation, this can be done with vocabulary words or people (Who am I?) for Science and Social Studies. Even in math, students give clues to choose a particular number.