If you ever wanted to write you own modules it might be useful to have an understanding of the myLANsite Database Schema. From the table and key-names, it should be pretty obvious, but as I like fabFORCE's DBDesigner that much, I just quickly reverse-engineered my database. I left out all the Joomla tables to keep it simple. And as I do not have a PDF printer here, I had to take screenshots and put them together in mspaint.exe. But it suits the purpose :)

Wherever you see a field called "userid" or "eventid", you know that it links to the "id" field of either the jos_users or the jos_mls_events table although these links are not displayed (to make it look nicer). 

http://www.mylansite.org/Downloads/task,cat_view/gid,43/

If you are looking for a Joomla! DB-schema, have a look here . Although it is based on the upcoming 1.5 version, not much has changed between the current 1.0.8 and 1.5.