This reference question isn't difficult or new (I talked about something similar back in 2007), but I still love this idea so I thought I'd share it.
A patron called and asked if I could search for a book for her by ISBN. When the search brought back no results, she said "well I'm getting this from an eight year old so who knows." Ha.
To verify the ISBN, I searched for it on Amazon, and sure enough it was a kids book on Paul Revere - published in 1986. I'm sure we had other books on Paul Revere, so I asked if she needed just information about him, or this particular book. She said,
No, I need this book. My niece got it out from her school library in Pennsylvania, and I wanted to read it with her over the phone.
Man I love this idea. I widened my search to include all the libraries in Massachusetts, and sure enough a few libraries outside my network had it. I requested it and the patron was happy. Since it's coming from outside the system, it might take up to a couple weeks to get here, but hopefully it'll arrive before the project is due.
So, another win for interlibrary loan, and also a win for staying involved in kids' lives despite living in a different state. Go libraries!