Today, while working in my office, I started hiccuping. After awhile my colleague that was working in the office with me started laughing, then giving advice on how to get rid of them. I tried holding my breath, trying to yawn, trying to burp, drinking water really fast, etc. I didn't try drinking water with my head upside down, like my colleague suggested, because I didn't want to end up with water all over myself.
After about an hour, I stopped by another colleagues classroom and asked him to come by the office at some point to try to scare the hiccups out of me. It was my last resort. As I was making my request, he told me to tell him when my next hiccup was going to be. Thinking that he was going to try to scare me right then I didn't take him seriously. He told me he was serious and to concentrate. So I did and found that I didn't know when the next one was going to come. Then I realized I had stopped hiccuping!!
He says it works every time. The act of concentrating on when your next hiccup is coming makes you stop hiccuping. Try it! Let me know if it works for you and it wasn't just a coincidence today.