http://www.youtube.com/watch?v=EZB0lLIcXIAI would assume from my own experience that this youth minister will make most, if not all of these arguments and Hitchens' responses to them are pretty good.
If they invoke Pascal's Wager, two ways to refute it are:
-If God doesn't exist but you live like he does, then you've wasted your life in an attempt to please someone who doesn't exist.
-Point out that the same wager could be made for any of the other hundreds of gods that humanity has believed in. Nothing in the wager points to worship of Abrahamic god over any other god and there's no more evidence that points to the Abrahamic god than any other god.
If they talk about the Bible as the source of morality, ask them what they think about the morality of keeping slaves, beating children who misbehave, of forcing women to marry their rapist, rape victims being executed for not screaming loud enough, of executing someone for working on the Sabbath, or any of the other reprehensible 'morals' in the Bible. If they disagree with any of them, point out that their morals must be coming from somewhere other than the Bible.
If they equivocate on Old vs New Testament hit them with Matthew 5:18-19 or Luke 16:17 which both have Jesus saying that the Old Testament laws still apply.
If they talk about the '10 Commandments' point out that the ten in Exodus 20 are just the first in a long list. After Moses comes down off the mountain sees the golden calf, he smashes the tablets and goes to get new ones. Exodus 34 then has a list of ten followed by, "And he wrote upon the tables the words of the covenant, the ten commandments." (Exodus 34:28) Those commandments are:
Exodus 34:17-27
1)Thou shalt make thee no molten gods.
2)The feast of unleavened bread (Passover) shalt thou keep. Seven days thou shalt eat unleavened bread, as I commanded thee, in the time of the month Abib: for in the month Abib thou camest out from Egypt.
3)All that openeth the matrix is mine; and every firstling among thy cattle, whether ox or sheep, that is male. But the firstling of an ass thou shalt redeem with a lamb: and if thou redeem him not, then shalt thou break his neck.
4) All the firstborn of thy sons thou shalt redeem. And none shall appear before me empty.
5)Six days thou shalt work, but on the seventh day thou shalt rest: in earing time and in harvest thou shalt rest.
6)And thou shalt observe the feast of weeks, of the firstfruits of wheat harvest, and the feast of ingathering at the year's end.
7)Thrice in the year shall all your menchildren appear before the LORD God, the God of Israel. For I will cast out the nations before thee, and enlarge thy borders: neither shall any man desire thy land, when thou shalt go up to appear before the LORD thy God thrice in the year.
8)Thou shalt not offer the blood of my sacrifice with leaven; neither shall the sacrifice of the feast of the passover be left unto the morning.
9)The first of the firstfruits of thy land thou shalt bring unto the house of the LORD thy God.
10)Thou shall not seethe a kid in its mother's milk (origin of the Kosher ban on meat and dairy)
Then ask the youth pastor how they've lived up to them (especially the blood sacrifices).