No shit.

I had a bad case of the hiccups last night, and as far as I remembered, the causes still aren't very well understood. So I went to Wikipedia to check it out. I thought I was familiar with most home remedies, but apparently not. I came across two "respiratory-based" remedies:

However, one respiratory remedy has a fairly sound rationale underlying it. Breathing into a bag or small enclosed container (ensuring that it is completely sealed around the mouth and nose) induces a state that is termed respiratory acidosis. The effect is caused by increasing the amount of inspired carbon dioxide, which then increases the level of carbon dioxide in the serum. These increased levels of CO2 lower the pH in the blood, hence creating a state of acidosis. This state of acidosis produces vasodilation and depression of the central nervous system. The effect allows for increased blood flow to the affected muscles, and suppression of the aberrant nervous impulses. Inducing a state of acidemia through hypoventilation is particularly effective in curing hiccups because the diaphragm rests directly against the pulmonary vasculature that is then flowing with especially low pH blood.

They note that this could be dangerous, as you could pass out. So be careful.

Also:

Additionally, another respiratory remedy appears to be of the most effective in treating persistent hiccups. One breathes out all the air that they are able to in one long exhalation then breathes in all the air they feel they possibly can in one continuous inhalation. The person then attempts to breathe in even more air in a series of short powerful puffs, until their lungs cannot hold any more. The person remains in this state for as long as they feel a small gas bubble coming at the very base of the throat, ready to be burped.

I didn't need to try the second one, cause I just wheezed into a paper bag for about a minute and my hiccups were gone.

Also, I thought they were making this shit up, but there are sources:

In 2006, Francis Fesmire of the University of Tennessee College of Medicine received an Ig Nobel prize for medicine after he published "Termination of intractable hiccups with digital rectal massage" in 1988. In an attempt to block the runaway messages on the vagus nerve, Fesmire found that stimulation of the vagus nerve by digital rectal massage worked, stopping a bout of hiccupping.

I think I'll stick with the paper sack.