Advent of Code may be the most epic computer science event of the year not named Strange Loop.
Because I'm still weak with more sophisticated logic, I primarily stick with the languages I know well (in this case, Erlang) although I may experiment with LFE this year if time permits.
Typically each day can be run by invoking day<n>:part1("input.txt") and day<n>:part2("input.txt"), although occasionally the inputs may not be in a file, and sometimes if I'm in a hurry I'll break the logic behind part 1 while extending it for part 2.
Files named "sample.txt" typically are examples from the problem specification used to test my logic.
I'll carry myio.erl along each day so that I can tweak its logic without breaking previous days' efforts. Frankly, though, it's gotten so long that I've forgotten how to use most of its functions; I'll probably write a test suite for it eventually so I have example code.