You can give your players incentive to do things, but if it’s not the incentive they’re looking for they will probably demonstrate it by their in game actions. Some examples of player incentives include:
Do you like electronic music? Do you like free stuff? Are you okay with amateur music from someone who's learning? Yes? Because that's what this is.
Quakecon 2011 Keynote Annotated
An interesting but technically dense talk about gaming technology. I translate it for the non-coders.
A programming project where I set out to make a Minecraft-style world so I can experiment with Octree data.
The Loot Lottery
What makes the gameplay of Borderlands so addictive for some, and what does that have to do with slot machines?
Batman v. Superman Wasn't All Bad
It's not a good movie, but it was made with good intentions and if you look closely you can find a few interesting ideas.