Free Spanish worksheets: SER O ESTAR. For some of these, either ser or estar would work depending on the context of use. You could have kids write a note about how the message changes based on which verb is used. https://es.islcollective.com/resources/printables/worksheets_doc_docx/ser_o_estar/ser-y-estar/67735
Spanish for kids: Color by Number in Spanish (Thanksgiving worksheet). Fun Spanish activity for kids to practice numbers in Spanish and colors in Spanish! http://www.enotes.com/documents/color-by-numbers-spanish-thanksgiving-worksheet-19421
Free Spanish worksheets to teach time in Spanish, seasons in Spanish, Spanish days of the week, months in Spanish and weather in Spanish. Free Spanish printables from PrintableSpanish.com http://printablespanish.com/free-time-weather-worksheets/
Fun for elementary Spanish. Even if it's not a required subject I think I would still try to incorporate it because kids learn faster and retain that information better than adults. Maybe have extra credit quizzes on it or something.