|countryimage_alt=A portrait of two men in 1970's suits.|caption=Carl Heath and Per Wetterstrand, organizers of OB7.|location=Varberg, Sweden
|name=OB7
|date=October {{start date|2002|10}}|homepage_urlwebsite=http://{{URL|ob7.se}}|homepage_link_text=OB7s web page|number_of_runs=1|number_of_playersparticipants=36
|duration=2 days
|full_creditsdesigners=Designed by {{plainlist|*[[Carl Heath]] and * [[Per Wetterstrand]].}}|participation_fee={{currency|900|SEK 900}}|game_mechanicstechniques=Several{{plainlist|* [[The Doctor]]* [[Pre-larp workshop]]}}
}}
'''OB7''' was a larp set in the context a prison during political turmoil in Sweden in 1973. The Swedish Security Police (Swedish: ''Säpo'') arrested people belonging to various leftist organisations and kept them in prison for interrogation on the suspicion of terrorist activities. The game was designed to explore gameplay in isolation.