Haven't touched it in a year and a half, but I used to have a lot of MTG cards - and cards for about a dozen other games (Illuminati - New World Order, Animehem, Over The Edge, a fantasy RPG one that I don't remember the name of, a Christian one I was GIVEN a set of cards for at GenCon a few years ago, and Monty Python and the Quest for the Holy Grail, to name a few...). I'm surprised no challenges relating to these have surfaced previously, to be honest!