How to motivate people to participate in a company hackathon?

[Wakan Tanka]

I'm sure that the motivation is the last thing that people from Numenta 
lacked, but I've come across this by accident and maybe some ideas are 
helpful.

http://workplace.stackexchange.com/questions/57596/how-to-motivate-people-to-participate-in-a-company-hackathon
Regards

Wakan