Wolfram Alpha? For What Do You Use It?

Ok, I don't know if you've heard about this yet, but this is a new sort of search engine.  WolframAlpha is billed as a "computational knowledge engine".  Instead of giving you long list of websites that contain the search term entered it gives you a concise view of the actual information for which you are searching.  

I'm just wondering who is using this right now, and how they are using it.

So far the primary use I've found for it is figuring out how many days I have until a given date.  Just type a date in and it will give you any pertinent information relating to that date.  Including the aforementioned calculation.  That is moderately useful, but not by any means earth shattering.  So what uses, if any, have you found for this new search engine?  Please comment!