What you have is a Beaucarnea recurvata commonly known as Ponytail Palm. I have one on my desk and it is very easy to take care of and doesn't mind being ignored.

They prefer bright light and can even be kept outside during the summer in full sun. Water is the key to this plants health. When you water saturate the soil completely but let the soil dry between waterings. In the winter, you will decrease the amount and frequency of the water. Use a very light solution of fertilizer every couples of weeks. If you keep this plant outside during the summer be sure to monitor the water that falls naturally. If the plant is kept moist all of the time you may incur problems.