http://www.techradar.com/news/tesla-owner-uses-free-supercharger-power-for-pure-bitcoin-mining-profit

As Bitcoin's value has continued to surge, interest in Bitcoin mining has exploded, but it's struggled to remain profitable because of how energy intensive a process it is - leading to many spending more on electricity than they earn in Bitcoin. 

Now one user has found an interesting way around the problem, by building a mining rig into the trunk of their Tesla. In doing so they'd theoretically be able to power their mining apparatus for free, and any Bitcoins earned would be pure profit.