It's my Ponytail Palm (Beaucarnea recurvata). I guess it's not really a palm, but is actually in the lily family. An evergreen perennial native to Mexico, it is the perfect houseplant for me because it doesn't require frequent watering - or much watering at all. I've had it for about four years and it has grown to keep pace with the size of the planter it is in. I've seen (in Mexico) that were 15' or more tall.
It's bottle-shaped trunk is cool, and looks kinda' like an elephants foot. The bulbous end is where it stores its water. I like the hard strappy leaves. It looks like it's exploding. It gets a summer vacation outdoors and ends up in the Harry Potter Garden because it's an odd looking plant and that's where they go to hang out with each other.