If the intention is to deliberately get drunk, they could have shots, which are usually drinks with a higher alcohol by volume percentage like tequila, whiskey or vodka (all usually between 30-40%). Shots tend to affect you very quickly and strongly however (from personally experience, I usually find it takes any alcoholic effect to take about 15-20minutes drink dependant), so maybe have them have a stronger mixer (I don't know if this is what they're called in the US, but it's usually alcohol and something else, like gin and tonic, vodka orange juice or jack Daniels (a brand of bourbon) and coke). A stronger mixer would mean a higher alcohol to mixer ratio.
Re: what would they drink?