A shot book, in popular college tradition, is a scrapbook created for someone's 21st birthday celebration. The idea is to take 21 shots (or drinks) and the 21 pages in the book correspond with each shot. Friends usually decorate individual pages with an assortment of pictures, stickers, quotes, and well-wishes dedicated to the birthday person. After each shot, the birthday person signs off on the page. It's a fun and creative way to celebrate this momentous event while simultaneously capturing the memories.