For 1, I don't really know. I'd have to think long and hard on it and come up with a scheme to enrich my life without running afoul of unforseen consequences.

For 2, I'd go permanently about 50 years into the future. Think about it--if you went back to 1990 with a PS3, people would have thought you were God. Imagine what will be out there 50 years from now. Not just game consoles -- all kinds of technology. New computers, new cell phones, new game consoles, vehicles, maybe even technology of a sort that hasn't even been conceived of yet.

50 years is a proper number; if you start going hundreds of years into the future maybe you run into a dystopia or find no living humans left, or a world changed to the point where it's become completely alien and you can't understand anybody. (Think of someone speaking Shakespearean English brought into the present day. Our intrepid Elizabethan would think he was in Hell). 50 years from now, the world will still be recognizable, people will still understand present-day English...it'll be the world we know, but improved.