I like the Excel Functions in Tableau idea.
I think a "how do you understand/internalize table calcs" / "how do you explain table calcs" session could be interesting. Joe did a great session on his understanding a couple of months ago, one of my takeaways from TCC12 with blog posts like this: http://www.tableausoftware.com/about/blog/2012/11/3-common-symptoms-tableau-doctor-office-19771 is that there can be more/better/different education around the subject.
Dustin, I can never get enough of calculations. So I'm with Jonathan, the Excel Functions in T sounds good to me.