As a retired soldier and current middle school science teacher I offer extra credit one time each year. I tell the students the story of LTC John McCrea, Canadian and surgeon for the British Army during WWI. If they can recite Flanders Fields correctly, I change their lowest grade for the 9 weeks to 100%. Then the challenge for them is to find someone selling buddy poppies on Memorial Day, buy one, tell him the story above and recite the poem. I only know if they did the latter if they tell me. Doesn't have a thing to do with science, but it does with their heritage.