Req: (Free) Embedded Platforms for Education

Hi all,

First of all I just joined this group so let me salute all members !!

I have a request and I would be happy is someone could help.

You all probably know that embedded systems are more and more
considered as hot topics to be though at universities. I will be in
charge of managing a complete course for graduate students on embedded
system with a focus on software engineering and operating systems for
embedded platforms.

Since having only a theoretical course is quite a boring activity : )
I am looking for the best platform students can experiment and play
with (doing labs, projects and so on)

Obviously, free and open source platforms are privileged since this is
an education purpose in a university that cannot afford paying money
for licences; or even managing a complex relation with an industrial
partner with some 'discounts' on licences.

So if anyone has a suggestion I would be happy to know about it. At
the end of the process, I'll send a table summarising all the
suggestions so other people/teachers could benefit from it.

Kind regards,