I have part of a school website running on Modx and hope to move the rest over at some time, but who knows when!
You can view the piece I have done here:
olneyfriends.org/summit/ - it is an information and discussion area, has embedded videos from youtube, and feeds from facebook (via twitter) and from twitter.
I will be working on a news, calendar and gallery areas - but nothing up yet
Off the top of my head I used: wayfinder, getresources, quip, filelister, some custom php and javascript (jquery), and some borrowed (open source) javascript.
I don’t think I will need anything else to implement an events, and calendar page. Edit: Actually taglister might be useful - but I have not worked with it extensively yet.
Others that might be useful would be: taglister, getfeed, formit, googlesitemap
Personally I find that unless a ’module’ really does what you want, or is very flexible (such as wayfinder ) or straight forward (filelister) that is often quicker and cleaner to write my own php/javascript - YMMV
Bill