One of the advances sought after in video gaming is games that respond to a players skill and either increase or decrease the difficulty on the fly. We are used to clicking "Easy, Normal, Hard, Eeeevil" and knowing that we'll get a slightly different experience in the video game. Take Mario Bros as an example. We can always make really sadistic versions of video games like this one (for a really really NSFW obscenities-laden version, watch here...I warned you!) but they do not gradually introduce challenges to us.
What is now being sought after is video games that adapt on the fly, so that if you complete a level with plenty of time to spare, the next level is a bit harder. The newest custom adaptation of Mario Bros (discussed here on Slashdot) not only gives you more enemies (like this video) but also puts holes in the ground and makes your technical skill increase on the fly.
In other words, instead of choosing a difficult path, the game adapts to your skill and increases or decreases difficulty based on your progress.
It strikes me that our own discipleship is the same way. It is a sad few of us want a hard bible study or Sunday School curriculum early in our discipleship or even late in it. I've seen Sunday School classes empty when a challenging series is began, reinforcing the UM Country Club status even more.
Perhaps what we want is a study or topic that meets us where we are and then presents us with growing questions. And we are sold study after study that purports to do just that.
While I've read and seen more curriculums and studies than I can count, there's only one that does this well: I've found that the Bible itself is the perfect incarnation of Mario Bros on-the-fly difficulty. Reading my marked-up bible and seeing my thoughts and comments from days of yore (especially as a youth) are really interesting and cause me to reconsider my own discipleship and thoughts. Skimming gets me one lesson, deep reading gets me another, reading a commentary gets me another, and then reading it alone lectio-divina style gets me another. No matter where I am in my discipleship, I get something out of it.
Perhaps if you are a Sunday School teacher and frustrated with challenging curriculum, take a cue from a parishioner of mine who is a Sunday School teacher 40 year veteran: just start reading the bible with the class. There's always something there, and when interest is piqued, then you know where to start deeper study.
You don't have to click "Easy Medium Hard." No one else has to know which difficulty you are at. All you have to do is start the game, and the challenges will come your way. Show up, play the game, and let the lessons come to you.