Passive/Side Businesses or Investments??

Has anyone been able to come up with ideas for passive investing/businesses – or thoughts on investments/businesses that you’d like to pursue if you had the money?

I am an attorney by profession, so I’m not looking to start a side business that I would run, as I don’t have the time for a bricks and mortar business, nor do I have the skills to be doing something like developing apps on the side. And I am already invested in the market – stocks/bonds (mostly indices, not individual stocks), maxing out the 401k etc.

But professional life has gotten pretty boring, and all I think about is law or the stock market. I’d love to have an investment on the side that could allow me to engage in/learn a different industry, even if I was just a minor silent partner. I’m thinking things like owning trucks in North Dakota that could be rented out or some small investment in another industrial business. (The North Dakota thing is totally made up and I have no idea if there’s any need – just fascinated by ND’s boom.) Obviously it has to be something that isn’t a money loser, but I’m not thinking about this with an intent to get rich and make millions; though I wouldn’t be looking to put in a huge sum – I can’t see putting in more than 30-50k to start.

What would you do if you could invest in anything? How would you find such opportunities – are there ways to connect with legit entrepreneurs looking for capital esp in the industrial/manufacturing spaces, if you aren’t working in venture cap or private equity?

It would be awesome if we could get a list of ideas going – whether realistic or just “fun” fantasy types of ideas of what you’d do if you wanted a side investment.

Angel investing? A la Shark Tank? Start your own mini-VC fund?