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You probably only need a table with eventid and userid with a joint primary key (`eventid`.`userid`)
Then to get the events, a user is going to, you just need to ask
"SELECT eventname, eventdate [and more info about the event] FROM [eventtable], [relationtable] WHERE [relationtable].userid=$userid AND [relationtable].eventid=[eventtable].eventid"
Or something like that.