While I see where peeps are going with the games for new players idea, to keep them simple and to help the new players learn, I have usually advocated a policy of getting players involved right away and treating them like one of the family, and explaining concepts and answering questions as the game progresses. Usually, after a game or two, a player knows enough about what's going on to be considered fair game.

While I try not to metagame, I do try not to murder or lynch a new player right off the bat; in the words of Jim Carrey as the Riddler- "Don't kill him! If you kill him, he won't learn nothin'!". Of course, if I have reason to suspect them, such as investigation results or they accidentally blurt out that they're guilty... well, what can you do?

In games involving team efforts like group actions, contacting new players and getting them involved in team efforts allows them to experience how it usually goes, so they will be prepared to lead their own efforts in future games.

Other than that, new folks rarely need help; the premise of the game is simple enough and there is no sure-fire winning strategy that works every time, so they're bound to get contradictory advice regarding strategy. Getting people involved and treating them like members of the group is much like teaching someone to swim. Sometimes you just have to jump right in.

That said, vanilla games more often wouldn't hurt.