Can you recommend a machine learning challenge that is suitable for novices?
You've already answered yourself by tagging kaggle.

Let me share the two competitions that I have every new hire in my team go through- and then have them keep improving their solurion for the next six months. These are a very well curated set of problems for a budding data scientist!


Titanic: Machine Learning from Disaster
https://www.kaggle.com/c/titanic
This one helps bridge the gap between an analyst and a data scientist, as well as eases you into the world of code from Excel.
Digit Recognizer
https://www.kaggle.com/c/digit-recognizer
The MNIST dataset has prepared almost every data scientist for the real world of dirty data, in a sweet, cushy manner. It makes very real the fact that not always will we have structured and organized data, but it should not deter us from gaining insight from it!


Happy Coding!