Started selling baseball cards at 8 years old. I had this database I'd put together with a software package called Q&A and I'd input the monthly data from Beckett's to see how cards were trending. It was all cash, of course, and I remember my mom being a little shocked when she found my money stash.

I used the same database, Q&A, to track where I caught fish on the lake we lived on to figure out the best spots given time of year, temperature, bait, etc.