Correct me if i'm wrong, but Vinyl is no more, and it is now called ARC. I was there on NYE and it is 18+ on friday and saturday nites, but dont expect to find anything at the bar other then gatorade, water, and red bulls

Place is kinda small, and if your looking for a well dressed, guido / meathead place to chill that is definately **NOT** the place to go lol
I've been likin the Exit Friday partys for the past two weeks (last nite was kinda off with the weather tho...) so it might not be a bad idea for Friday nite.
If you wanna venture into NJ during the week, Abyss in Sayreville, NJ has a good party on Wednesday nigtes thats 18+, and Metro Lounge in Rochelle Park, NJ has a decent Thrusday nite 'college party' or some shit thats 18+ too.
As far as SF goes, the place is technicall 21+ but rumor has it that you can get in even if your under 21 after about 5AM on sunday morning (after they stop serving alcohol)- but that can be hit or miss. I'm under 21 and never felt like making the trip at 5AM and be turned away so I cant speak for the party, but most of the people that I know that have gone there have liked it....
As far as hours go:
EXIT Fridays: 11PM till about 8AM Sat Morning
ABYSS WED: 9PM-2AM
METRO: 10 or 11P - till 2 or 3
hope that helps!
b