The SIGGRAPH Logo Gallery is an homage to (a specific instantiation of) the creativity and playfulness of the SIGGRAPH research community. It's also a fun way to explore and discover cool papers you might not have seen before (clicking on a paper's title will bring up more info, including the figure caption and a link to the paper). The Gallery was created by and is maintained by Daniel Ritchie.
Ultimately, the goal of this Gallery is to be a complete archive of all relevant figures that have ever been published. If you know of a paper that has such a figure in it that isn't already in the Gallery, please send me email and let me know about it!