Because I have read so many excellent DIFT challenges, and am sure I could never follow them with any degree of success, I am switching up the generations. Here is the way I will be playing them:
Gen 2–science and earth
Gen 5–Stay at home
Gen 13–Service sim/firefighter
Gen 15–half sibs
There is the possibility that I will throw some others in there somewhere, as I do love my sims!
If you are not familiar with the DIFT rules, here is a link that explains them: http://angelofafallen.livejournal.com/818.html#cutid1