I dunno, the idea of open-source software and good interpreted languages would get you pretty far. I wouldn't mind being Larry Wall - and I'll bet at this poin

I dunno, the idea of open-source software and good interpreted languages would get you pretty far. I wouldn't mind being Larry Wall - and I'll bet at this point I could re-implement Perl from memory pretty well. A decent knowledge of things like unit testing could also make you pretty damned effective in the then-burgeoning market of custom software. You might be able to pull a Google or a Netscape with a small team you hired from your consulting profits. With a decent knowledge of what tech was coming down the pike next year or so, I'm pretty sure you could do pretty well any time back to 1975 or so. Beyond that, I'd need research, because I didn't live through it - but if you know which year you're going for, check the patent database for anything invented about five years later than your target. That takes you back to the 1700's. Further back than that, you're talking about agriculture (crop rotation, for instance) or stirrups or something. Give me a target year and six months of prep time, and I'm virtually positive I could put together a killer business plan that would leave me or at least my children owning the world.