Of, I love this idea! I wish I had thought of it when I was teaching Macbeth last year.
I think the purpose of the game would be to become and stay king of Scottland. The first thing you would have to do is try to get the throne by killing Duncan. Then you’d have to stay in the throne by killing other people, and doing other nefarious deeds.
Great idea for a project. I think the first thing to do would be to map out Macbeth's life, as we know it from the play and then also extrapolate a bit. For example, we know he's a general, so he must have started as a soldier and had to work his way up the ranks. At some point, he got married so you can include that as well as you build up to the 'main events' in the play.
Somewhere on the board you'll want to have the Witches, perhaps you spin a wheel to get a prophesy? At the end, Macbeth must die but perhaps you can make some choices besides just what the play says, such as Macbeth kills himself, is killed by some other characters, etc. Good luck!
Wow! You could really have fun with that. Various professions could range from King to soldier to peasant. You could incorporate killing a character to move forward in the game, then feeling guilty about that murder to move backward. Somebody becoming suspcious of your actions could stall your progress, etc. etc. Basically, anything in the play that contributes to Macbeth's success could be used to advance a token; anything that leads to his decline would create a penalty or movement backwards.
I'm willing to bet you could could earn some impression points by incorporating some of the Scottish history around those events also. Things like how Shakespeare characterizes Duncan and Macbeth almost completely opposite of who those characters really are, that historicall Banquo never really existed, that Shakespeare wrote the play for James I of England (James VI of Scotland) who was a direct descendant of Malcolm III of Scotland (the Malcolm in the play), etc. etc.
That's a fantastic assignment! Have fun!