From an AskReddit member: "Go to a hotel and say you think you lost it there. It's the #1 most left behind item at hotels, so most places have a big bin filled with every phone charger imaginable. [Reddit] UPDATE
UPDATE: I just received this note from a reader on the subject:
"I work for the second largest conference hotel in my city. You have no idea the size box we have of chargers left behind. 90 percent are idiot blackberry chargers. This works 100% of the time, we never verify that anyone stays here we just let them go shopping for there charger. Hell we even will give people a charger if they call down to the front desk and say they forgot theirs!"