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:
The Witch Watch
My first REAL published book, about a guy who comes back from the dead due to a misunderstanding.
Steam Summer Blues
This mess of dross, confusion, and terrible UI design is the storefront the big publishers couldn't beat? Amazing.
Secret of Good Secrets
Sometimes in-game secrets are fun and sometimes they're lame. Here's why.
A horrible, railroading, stupid, contrived, and painfully ill-conceived roleplaying campaign. All in good fun.
How to Forum
Dear people of the internet: Please stop doing these horrible idiotic things when you talk to each other.