Be forewarned. I don't think many hostels would appreciate rowdiness in their establishments. Hostels, called "hostales" in Spanish, are family owned and operated budget hotels and are usually for singles or couples. You might want to consider a youth-hostel instead (called "Albergue Juveniles" in Spanish). There are few in Madrid and you're more likely to find young, like-minded partiers.
Do a search in this forum using MADRID YOUTH HOSTELS and you'll find the previous postings listing the youth-hostels in Madrid.
Still, you could always book a hostel and do your partying OUTSIDE the establishment and use the hostel only to sleep.
Good luck and have fun! Saludos, MadridMan
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