The Contoso demo for Dynamics AX is an extensive data set that covers most features in the application. You do have to get to know the company somewhat, but it is a great tool to do demos on.
The issue is to get up to date data, so that the BI reports and data looks current. Well… not any more.
If you need to refresh a demo set, you simply generate new data.
There is a module called demo data. Access this and click Generate data.
There are some options to consider. I normally tick them all…
Then just let it work for a bit…
You’re good to go do a demo with fresh data!
dyntips.com by Fredrik Sætre 
How long does this run normally? Mine is at 3hrs and still running.
Just a couple of minutes in the online demo environment.
I’m currently generating the demo data in an on-premise environment. And is at the 3hrs30mins mark and still counting.