I use this activity with Kindergartners (though older grades might like it too) when learning Spanish color vocabulary. The students love to see their color words appear magically! They write the color words using a white crayon, then color over the word using that color marker and the word appears!
Directions are on the sheet along with the spelling for each color word:
verde, rojo, negro, azul, and morado.
**Note, it helps to remind the students to push hard when using the white crayons, and the markers should be nice and juicy!