Dave's began life as a fin de siecle hostel for immigrants coming to Berlin to seek their fortunes in Germany or wider Europe. It has retained its liberal attitude and is now one of the city's most welcoming and open establishments.
Gay, lesbian, straight, any religion or none... Dave's tries not to turn anyone away unless they arrive with a chip of intolerance on their shoulder, or in groups of more than four (there simply is not the space to accommodate larger parties). Smoking is strictly banned, forging new friendships with an international bohemian crowd actively encouraged, and all the standard hostel stuff such as wi-fi and self-catering facilities are of course include.
Try also Fabian's and John's hostels nearby, which share the same philosophy.