What's the best way to find a co-founder?

I'm an Australian that works in the professional services industry, so I don't have time to go to incubator meetings which are typically held during the work week. However I am keen to meet some like-minded folk that are interested in starting a business - at the start as a project outside of their day job.

How does HN suggest I go about meeting such people? Unfortunately networking in my industry won't be possible due to restrictions in my contract.

Keen to hear your thoughts.