The hip, the queer, and the drunk.
Chueca's central pit stop, right off of the plaza. Pregame and schmooze while vying for an empty table as the crowd thickens, or take your drink to go (handy plastic cups make botellón-ing possible).
You won't mind the cafeteria lights as you sip your 5 euro "mini" (actually a liter of alcohol). Go all out and try the Calimocho - equal parts wine and Coca-cola = classy.