This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
This is a bit open, there are lots of applications you can use JavaFX in.
Probably best to briefly describe an intended or hypothetical application and then ask if it would be appropriate to use JavaFX to implement it or parts of it.