It's usually just a chocolate cake with TONS of red food coloring. Doesn't have to be if you make it properly, but 99 times out of 100 that's what people do.

Usually has nice cream cheese frosting though! <img src="http://www.traveltalkonline.com/forums/images/graemlins/Smile.gif" alt="" />

If I can't be a good example, I'll just have to be a horrible warning. [Linked Image]