Ask HN: Grad Group code dev project

Hi am going to be running a "Bootcamp" with 30+- new graduates straight out of university who are joining our company. And need your help with some ideas:

Here is the info:

Our module will be .net based.

To limit the amount of project we want groups of 5 people (6 groups)

Some of the grads have comp science backgrounds and some don't. Cater for about 5 people with no experience in coding at all(They will ultimately form a business analyst role in the company)

We are looking for a fun project to take them through the basics of visual studio, MVC, entity framework, layered architecture and some web dev.

It will run over 5 days.

Any ideas on what will be fun interesting and content rich?