The “known in advance” factor could also create some interesting days that make other teachers and students wonder. I’ll take increased curiosity almost any time I can get it. 🙂

I like the flexibility where you could surprise them by not telling them what you’ll collect the next day or give them a heads up by saying, “tomorrow I’ll be keeping track of who wears purple.” sort of thing. The reason I like this last one is because it lends itself to mob activities your students could do around campus. “Did you notice that all those students are dressed like Best Buy employees? Yea, I think all those kids are Mr. Fenton’s students.”

Not sure if this is what you were looking for with data, stats and probability. Keep me posted.