Thanks to Mark’s limited high school French and my iOS translator, we managed to figure out the basics of getting a pass for the Paris Metro.
Similar to London’s Oyster Card, the Paris Metro uses a Navigo Card. For non-residents, it’s called a Navigo Découverte card. It gives you unlimited access to their public transportation system (subway, buses, etc) for an entire week, starting on Monday @ 12:00am, and ending on Sunday @ 11:59pm (therefore, if you arrive on a Thurs or Fri, you probably shouldn’t buy it).
It costs 5€ to buy the card (good for 10 years) and 19,90€ to charge it up for the week, as long as you stay within Zones 1&2 (where all the touristy stuff is anyway). A one-way ticket is approx. 1,70€, so if you ride the train at least 10x during the week, you’ll have already made up for the cost.
You’ll also need a passport-sized photo that gets affixed onto your Navigo card, and there are plenty of photo booths in every Metro station where you can get a set for 5€. (Hey, this is starting to add up!)
You can also buy ticket packets if you don’t plan on traveling by bus or subway as much. For 2 weeks in Paris starting on a Monday, getting a Navigo card seemed like a pretty sweet deal.