I think Frankie Muniz made quite a bit of cash from owning parking lots. Gotta do somethin' with all that Malcolm in the Middle money.
Fun fact: He also does auto racing. He's pretty bad so I guess his teammates refer to him as 'Malcolm in the Back'.
The problem I see with getting into obscure investments before FI is the risk. For me, I'd rather get a basically guaranteed high ROI as with the stock market than go gambling.
However, each year after maxing my Roth 401(k) and Roth IRA, ESPP, etc. I venture a little outside the box.