Siri is seriously cool (c'mon, have you told your iPhone you love it?).
Wolfram Alpha is seriously cool.
Here are some fun hints on how to combine them: http://www.tuaw.com/2011/10/28/10-cool-things-you-can-do-with-wolfram-alpha-and-siri/
How about this: Say to Siri, "Ask Wolfram what flights are overhead" to find out which jet contrails are over head.