Werewolf
eblong.com
A summary and game history. Also has links.
Graduate Mafia Brotherhood
princeton.edu
Lists variants and rule suggestions. Provides a member list, rules, and a game and event history.
Loony Labs: Are You A Werewolf?
wunderland.com
A commercial release.
Mafia
stud.ntnu.no
Provides rules, scoring information, tactics, and a summary.