Coming up with a Game idea should be the easy part… I come up with them all the time, every other day a new idea for a game pops into my head, Its getting the time to develop them that’s the problem.
And if this is an assignment you should be coming up with your own ideas, though I will say if its got to be finished in 6 weeks make it small and simple, maybe have a look at onegameamonth.com for some ideas of things that were possible in a month.