I was going through some old items and came across this link for an on-line ADFS lab. I decided to run through the lab (takes about an hour). There are problems with it. The title of this blog tells you what these problems are.
I can tell it's an old lab, the manual tells you to enter the federation server url like:
https://adfsserver.treyresearch.com/adfs/ls/clientlogon.aspx - specifying the clientlogon.aspx file was how things were done up until beta 3 of R2 if I remember correctly.
You can get it working (just look around and get creative with the certs)
If you want some practice working with certificates used in ADFS - then you should check it out.
I submitted feedback and will try to locate who controls this content - but it will most likely be up there and in this condition for a while.
The online lab is a cool idea - too bad this is the only one I can find (and it's broken)