Ride the Rails

Can you buy advanced subway tickets or a 2 week long pass for all lines in Tokyo?

There are one day tickets and some 2-day tickets. You could theoretically buy multiple of them. But they are likely to come more expensive than using regular fares with a prepaid card or so. Here are the details:
http://www.japan-guide.com/e/e2017.html

You really don't need to, you can buy tickets on site, trains that operate in the city are unreserved seating commuter/metro type trains.

No one pass covers ALL the lines in Tokyo, there is a day pass that covers Tokyo Metro, Toei and JR, however I find this pass to be a real waste of money unless you really really really put it to use.

http://www.japan-guide.com/e/e2017.html

Thanks for the info guys. I was just trying to make train hopping easier for myself. Finding the right train is going to be hard enough, i've been told. lol I'm so excited I could just burst! Is the day pass you are talking about similar to the all day train and bus passes in the US? It sounds like i'll have to buy more than one ticket per day anyway if no one pass covers each of the lines. I'll be jumping around Tokyo, and I'll be going to Yokohama twice for sure.

Thank you so much for the link. That was SUPER helpful. I think I know where I'm going now. But getting lost is half the fun too isn't it? lol

USAAngle it is not that difficult.

Read the pages, I suggest you get a Suica/Pasmo card instead.
This eliminates the need to buy a ticket each time you ride, just charge the card with money and tap and go.

The all day all lines pass is expensive and I doubt the average traveler can pay it off.

The individual lines passes might, depending on how much you travel.

I use the JR Yamanote line in Tokyo 99% of the time. it takes me to most of the places where I want to go. The 2 exceptions are the Yurikamome to Odaiba and the Arakawa tram line to Zoshigaya but returns tickets aren't that expensive.