This year's Def Con entry badge was a working sampler keyboard, it even has a built-in puzzle that requires specific note inputs and linking with other badges. : r/synthesizers
DEF CON 30 Human badge – DEF CON Merchandise
Sneaky Badge, Defcon 31, BadgeLife badge from DEF CON 31. Includes extra letters | eBay
Pirate Jack Badge - Defcon 31 - 2023 from technick on Tindie