Ever have one of those moments where someone says something and your either silent or vocal reply is "Challenge accepted!"?

I did today. So I am sitting in class and the prof. was discussing the department's (philosophy) grading policy: they do not give more than 25% A's. This is kinda annoying, yet I sorta get it...sorta. I actually do not agree with such a policy but that's the beast that universities are. Anyways, because she's a new prof and had graded a little too easy last semester, she indicated that getting an A for this class will be rather difficult. Challenge accepted. Most of the mark is two papers, and to get an A we need to refer to at least two commentaries outside course materials. Should be easy enough, especially given that it is an introductory course on Aristotle and late Hellenistic philosophy.

So my fellow EoFFers, what has been your most recent or memorable (any moment really) of "Challenge accepted!"?