You have a time machine . . .

[ThePresence]

I would go back 20 years prior to the first American colonists, and help the natives build up a resistance to diseases, while getting them to form a confederation of tribes. I would get them to construct the first of many fortresses where tribal councils would meet and participate in commerce.

And why would they listen to you? You probably won't get very far, for many reasons.
Read Time Machines by Paul Nahin. The time paradox doesn't really exist. You won't be as successful as you think. Can you change the future? No, of course not. But you can influence the future. So when you travel back in time, you are now facing the past as the future. Can you change the future? No. You will not be successful in killing your grandfather, something prevent it from happening. If you don't buy that argument, you can just go Multiverse and never have the issue to begin with.

 

[M0oG0oGaiPan]

I'd travel back to the time this forum was running on fusetalk and the op was always time traveling.

 

[PottedMeat]

You would go back to when you were kid, be in the room with your kid self while kid self was playing with himself, then help him pull his pants up as the mom walked in?

reminds me of this

 

[reallyscrued]

I'll go back to the point when Apple stock was at the lowest and buy a few thousand shares.

How do you know that the small actions or even the fact that somehow now you own some Apple stock won't set off a chain reaction that causes you to be poor, alone, or even dead?

Don't fuck with the past, man. It's like you guys forget the rules Sci-Fi has taught us.

 

[Platypus]

I'd prevent my birth with said machine

 

[sixone]

Easy question. The largest Powerball win ever was in February of 2006. I'd go back to the start of that year with the wining numbers.

You'd only get half. Better to win the drawing before that big win, so that you're the only winner.

 

[M0oG0oGaiPan]

reminds me of this

lawl