Consider Bastiat's That Which is Seen, and That Which is Not Seen
Previous Economics is Fun topics...
Part 1: Value
Part 2: Price
Part 3: Specialization
Part 4: Trade
Part 5: Time
Part 6: Money
Part 7: Middlemen
Part 8: Speculators
Part 9: Joint Enterprise
Part 10: Taxation
Part 11: Competition
Part 12: Banking
Part 13: International Trade