Vocabulary Challenge: Run through 1 – 50. Feel free to distinguish between numerals, cardinals, ordinals etc.
Grammar Challenge for @Sanonius: Translate this stele out of Ancient Greek.
Grammar Challenge for Everyone Else: Here is the English translation; put it into another language.
Translation
This is the sign of Arniadas who was destroyed by fiery-eyed Ares fighting close to the ships on river Arachthos’s flows, greatly excelling in the uproar of the battle that brings lament.
Extra challenge: Explain the names and titles of at least ten historical rulers.
Extra extra challenge, just for the Japanese learners: Explain the names of at least ten eras.
Challenge not for the Japanese learners 
Create new Go terms