When I moved in, this was in the backyard. It recently sent up a very tall stalk.
Drought Smart Plants reply: Wow, what a surprise! I would say, without a really close look a the leaves, that this is some type of Aloe. I'm sorry I can't be more specific, as there are just too darned many of these incredibly interesting plants. The typical leaf form is succulent to varying degrees, with thorns or projections along the edges. These are usually not harmful, but fairly soft.
The blooms, as you have found out, are arranged up a spire, and generally are bell shaped. These flowers will attract hummingbirds if you're lucky enough to have some nearby.
This plant actually looks like it needs to be in more light - the Aloe genus is very partial to extremely bright and hot areas, making it a perfect candidate for xeriscaping.
Hope this helps,
See these pages for more:
Aloe Succulent Plants
Just in case your plant has sharp spines at the tip of each leaf, indicating a different kind of creature altogether, check out the page on Agave too.