The Free Adventures link from WotC has gone away.
The WotC website is horrible about integrating their old content with their new content. The 3.5 Archive is still there, but all the links to the modules still need to be handpicked and found. I'm fond of The Thunder Below myself, which has plenty of encounters which can smother the PCs should they not be careful.
See the FAQ for all games at home. http://dndadventurersleague.org/tag/faq/ the purchased adventures can be used for home games and legal all characters