Event.observe('activity1', 'mouseover', function(e) { $('activitylist1').show(); } );
Event.observe('activity1', 'mouseout', function(e) { $('activitylist1').hide(); } );

Event.observe('activity2', 'mouseover', function(e) { $('activitylist2').show(); } );
Event.observe('activity2', 'mouseout', function(e) { $('activitylist2').hide(); } );

Event.observe('activity3', 'mouseover', function(e) { $('activitylist3').show(); } );
Event.observe('activity3', 'mouseout', function(e) { $('activitylist3').hide(); } );