Question: What activity has been a reoccuring event in San Diego since 1998?
Answer(s):
answer: Rock 'n' Roll San Diego Marathon

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.071vr)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.071vr ns:travel.travel_destination.tourist_attractions ?x .
?x ns:time.recurring_event.date_of_first_occurance "1998"^^xsd:dateTime . 
}