poor thing....it has lost 90% of its leaves. it definitely looks like a sedum. Sedum pachyphyllum?

Difficult to tell in such poor condition, agree with Christina, could be S. pachyphyllum, or could be S. allantoides?

How much sun does this plant get? While I do not know the exact name of yours but I'm sure between the comments above and more to come that you'll find out sooner or later. I agree that it is a Sedum. The main problem with your plant is lack of proper sunlight. Just EASE it into more and more sun until it has the amount of sunlight that is recommended. I think this plant has potential to have a strong comeback if you take good care of it. As I've learned with my other plants, all succulents need the same care in 2 basic areas...most importantly a pot with a drainage hole and proper soil that drains fast while still providing enough water AND (as I stated above) proper amounts of sunlight. Most succulents don't like to have wet 'feet' so the main thing to watch out for is rotting from soil that stays too moist. After you know exactly what it is then you'll be able to find out where the plant naturally lives and then you can change the soil to accommodate the conditions such as your temperature and humidity and such. Good luck!