I'd repair our education system or replace it with something that works.

I'd visit the near future, close enough that someone might want to talk to Larry Niven and can figure out the language; distant enough to get me decent medical techniques and a ticket to the Moon.

The witnessing of titanic events is always dangerous, usually painful, and often fatal.

The dinosaurs became extinct because they didn't have a space program.

There is no cause so good or noble that it will not attract fuggheads; and the fuggheads will get all the press.

Anything you don't understand is dangerous until you do understand it.

The perversity of the Universe tends towards a maximum.