maxh

"Where is the evidence for this [forbidden fruit effect]?"
"Although conventional wisdom presumes that a prohibitory law will have the desired effect and lawmakers act in accordance with such 'wisdom,' careful studies of the operation of the laws often show the opposite effect: the behavior they are supposed to inhibit actually increases" (Filley, Dwight. Forbidden Fruit: When Prohibition Increases the Harm It Is Supposed to Reduce. The Independent Review. v.III, n.3. Winter 1999.).

"While they may exist or not (my opponent has yet to show they are a common occurrence), they only affect those in the parties. The government should be limited to protecting people from others, NOT people from themselves."
Except that, since the people attending such parties need some form of transportation home, and traditionally 'safe' transportation, such as taxis, are not available (as they would increase the risk of being found out), attendees tend to use their own private cars, which increases drink driving.

"I'm sorry, but this bit is very confusing. Can my opponent clear this up? This way I won't commit a strawman."
There are two relevant ways to reduce drink driving: punishing the activity itself and punishing underage drinking for the chance it will result in drink driving. Since (assuming equal enforcement, of course) punishing drink driving affects everyone, and only those who are actually causing danger, and the drinking age affects only those under 21, even if they are not causing danger, drink driving laws are preferable to a drinking age.

"Why is there a voting age?"
I just covered this (http://www.debate.org/debate/7645/)

"adolescents with less impulse control"
But such impulse control problems are caused by age restrictions such as the drinking age. See Dr Epstein's infantilisation theory (Epstein, Robert. The Case Against Adolescence: Rediscovering the Adult in Every Teen. Quill Driver. May 2007.).

"Drunk driving is an obvious example, and allowing alcoholic drinking to go rampant just worsens the situation."
Actually, the drinking age (slightly) increases drink driving. "States that did not raise their MLPA�s [minimum legal purchase ages] during the 1976�81 period experienced a slightly larger decrease in fatal crashes among drivers under twenty-one years of age than did those states that did raise their MLPA�s. The difference is not large enough to be called significant, but it does suggest that raised drinking ages are not associated with any net reductions in fatal crashes by young drivers" (Males, Mike. Raising the Legal Minimum Drinking Age on Involvement in Fatal Crashes. 1986.). It's not a significant increase, but it's certainly not a decrease.

"When you are trying to compare the collective thinking of an entire NATION to another, then you are stepping in very very very muddy waters."
It's not comparing the US to another nation, but rather to every nation in the world: the US has the world's highest drinking age (http://www2.potsdam.edu/hansondj/LegalDrinkingAge.html). Of particular note are Armenia, Azerbaijan, China, Fiji, Nigeria, Poland, Portugal, Georgia, Thailand, and Vietnam, which have no drinking age at all.

"Even if we abolish the drinking age, people will always think of new ways to drink an abhorrent amount of alcohol and die in the process."
Of course, but at least "21 for 21" would become "0 for 0". Let's see someone dying of alcohol poisoning that way.