For your husband, a great Christmas gift idea would be a subscription to a coding competition website, such as TopCoder, HackerRank, or CodeFights. They offer a variety of coding challenges and competitions for individuals to participate in, allowing your husband to continue to develop his skills and feed his competitive nature. Additionally, you can consider purchasing him a gift card to his favorite online programming tutorial, Udemy or Codecademy, for him to further develop his coding skills.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.