David Sparks is my kind of nerd:

Maybe it’s a lawyer thing but I quite frequently need to calculate dates. For instance, I need to figure out what day is 30 days after I serve documents on somebody or how many days elapsed between date X and date Y.

I was thinking this would be really convenient if I could do it with Siri but the Siri documentation doesn’t say anything about calculating dates. After a little experimentation, however, I stumbled upon the necessary syntax:

Why are you still here? Go.