PartyIntents examines whether portal survey methods could be used to anonymously survey gay and bisexual men about HIV-risk behaviors before and after a weekend party–oriented vacation. The study recruited 97% of eligible men and of these 489 participants 47% completed the follow-up assessment. Approximately one half of the men intended to use illegal drugs over the weekend, and almost 20% thought that they might have anal intercourse and not use a condom. The methodology can be applied and provides useful information about HIV risk at these events, though refinements may be needed to increase the follow-up rates.