Last year, the challenge was called something else, but this use-it-or-lose-it year-long challenge in the Stash Knit Down group is called the Stash Diva Dash. Presumably it's a pun between diva (a temperamental woman) and a heavily-accented version of diver (as in stash diving); I don't really know, and it's not really important.
The purpose of the challenge is to select 13 skeins (some choose 13 lots- insanity!) of stash yarn, preferably "mystery" yarn. Since I went through a period of turning all my hanks into yarn cakes, and discarding the labels because "I will remember," I have plenty of mystery yarn, though I don't limit myself to mystery yarns for this challenge.
Here is a terribly-lit photo of my yarns for this dash. Left to right, in columns: 2 cakes Colinette Prism (Moss and Fire, I believe), 3 cakes of mystery wool, 4 skeins of Malabrigo Silky Merino in Sand (needs to be overdyed), 1 skein Lang Tosca, 2 cakes mystery-yardage mill-end handspun bfl, a tiny quantity of cashmere-silk handspun.