Badges / Achievements are getting very popular these days, and they seem to be a great way to promote community involvement.
Basically they're token awards you get for completing goals on the site.
I suggest that the Pod101 network implement them! There can be very fun to earn, and more importantly, make the site more engaging to the users...
Polyglot: Complete Beginner Lessons on more than one *Pod101.com site.
Forum Fan: Post at least 5 messages in the forums.
Hittin Your Stride: Completed 30 or more lessons.
Oyaji: Completed at least one Upper Level series.
Sensei: Completed at least 6000 Vocabulary correctly in the Flashcards.