Game: Diggy's Adventure

If you play freemium Facebook games to any degree, then you know how "Energy" systems work. You can play the game as long as you have a supply of little cartoon lightning bolts, but as soon as those are gone, you need to cough up some real dosh or you're kicked to the curb to dry out. Diggy's Adventure is a Facebook adventure game that tries to work with the Energy system instead of in spite of it, and it actually succeeds. More importantly, it's fun to play.