The activity-related success that I enjoyed the most happened down in the dungeons. Cody loves giving musical challenges in which he posts excerpts from songs and asks you to identify them, but during Slythmas he altered the songs a bit to make them nearly unrecognizable.
After a lot of listens, I was able to identify about half of them... until I discovered the trick. The songs all sounded like they were dubbed over by “Alvin and the Chipmunks”, so I Googled to figure out exactly how this was done... there are Muggle devices that allow you to alter the “frequency” of the song to change its sound. So I guessed that if I changed the “frequency” back, it would sound like the original! I tried this hypothesis on one of the songs I did recognize, and three tries later I was rewarded with the sound of the original recording! Repeating this transformation on the other songs... and I could finally finish Cody’s task! Even if I managed to accomplish many other things that year, this song identification has to be my most satisfying HOL moment of 2017-8.