Math/puzzle auction for Gathering 4 Gardner

Gathering 4 Gardner is an organization that puts on a conference every two years celebrating the ideas of the celebrated math writer Martin Gardner. Right now, they have a fundraiser auction that includes puzzles, signed books, and even props from Vi Hart's YouTube videos! Over the years, I've seen lots of questions on r/math about buying gifts for mathematicians, and this auction is a treasure trove, so I thought you all might be interested in seeing it! (I'm not affiliated with the fundraiser other than that I attend G4G whenever I get a chance!)