Building a workshop website I am organizing a one day workshop as a part of a major conference in my field.
I would like to have a website to


introductory text (static html)
announce things (some content management)
keep everybody up to date (mailing list)
maintain a pre-workshop and post-workshop online discussion forum


Is there a web service that would implement these things easily?

Also, I don't want the visitors to register accounts. Perhaps a mailing list accessible via web would be sufficient, since I do not expect anybody to regularly visit just to check the forum (except for myself). Is there a mailing list/forum service suitable for such purpose?

Free would be best. I am capable of building such website myself, but I do not want to host it nor spend too much time setting it up. In the past, I used wordpress.com, google sites, google groups and such...
Some large institutions maintain platforms for such tasks: some of them are restricted to their members, others have a more liberal policy. For example, the French CNRS (largest national research institute) has developed SciencesConf.org. It fulfills your requirements, except for the forum (which, as far as I can tell, is rather unusual for conferences to have).