[patcoll]

Promote the hell out of it on Twitter, Reddit, Hacker News (done). Apply to speak at conferences and go speak about it. There are plenty of PHP conferences to choose from. Get your employer to pay for the trips.

Other ideas for passive income:

http://needwant.com/p/buying-apartment-airbnb/

[RobAley]

Thanks for the tips, the conferences idea sounds interesting (though my employer has no budget to fund conferences related to my work let alone anything else, so I'd have to cover the costs myself).

Not sure about the real-estate idea, I guaranteed my wife that any money-making schemes would be strictly low-risk!

[aestra]

Not only is buying an apartment to rent out short term on a full time basis high risk, its probably illegal. This specific post was on HN and we found he was violating his homeowners agreement as well.

It's also a bad idea insurance wise, what if something happens (fire, flood, robbery) and your homeowner's insurance says "we are covering a home, not a friggin unregulated hotel"