You can read more about masturbate-a-thon on Wikipedia:

and the other officiel sites:
1) San Francisco: http://www.masturbate-a-thon.com
2) England: http://www.masturbate-a-thon.co.uk/
3) Oregon: http://www.masturbate-a-thon.org/

Some other linkes about the event:
http://ekstrabladet.dk/sex_og_samliv/article961953.ece

http://side6.dk/articles/showarticle.asp?pageid=3907&areaID=31

http://avisen.dk/blogs/artikel/onanikonkurrence-koebenhavn-090108.aspx

http://politiken.dk/indland/article457261.ece

http://www.dr.dk/NETTV/Update/2008/01/14/20080114203857.htm

http://www.chilinet.dk/default.asp?id=403&nid=3547

http://www.berlingske.dk/article/20080114/kultur/701140008/

http://www.jmnoticias.com/index.php?action=fullnews&id=337