These are the things I've been able to do in the past year or so that I thought were pretty interesting and enjoyable:
* Code to render PDF's into images using asynchronous streams to make it extremely fast.
* The same thing for videos, to recompress them for delivery to iPads.
* Code to use AWS to create a service that can be fairly easily scaled up and down dynamically in response to demand.
* Creating a highly tuned Node.js server capable of serving thousands of requests per second. Even basic CRUD operations can be pretty interesting to code when you are fine tuning server system level settings, optimizing database queries, using caching, etc to make sure that response times are all around 10-15ms even at hundreds to thousands of requests per second.
* Code to render PDF's into images using asynchronous streams to make it extremely fast.
* The same thing for videos, to recompress them for delivery to iPads.
* Code to use AWS to create a service that can be fairly easily scaled up and down dynamically in response to demand.
* Creating a highly tuned Node.js server capable of serving thousands of requests per second. Even basic CRUD operations can be pretty interesting to code when you are fine tuning server system level settings, optimizing database queries, using caching, etc to make sure that response times are all around 10-15ms even at hundreds to thousands of requests per second.