Question: What stadium is home to the NFL team that won the 2009 championship?
Answer(s):
answer: Heinz Field

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ?c)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
?c ns:sports.sports_team.championships ns:m.0_gt_lv . 
?c ns:sports.sports_team.venue ?y .
?y ns:sports.team_venue_relationship.venue ?x .
FILTER(NOT EXISTS {?y ns:sports.team_venue_relationship.from ?sk0} || 
EXISTS {?y ns:sports.team_venue_relationship.from ?sk1 . 
FILTER(xsd:datetime(?sk1) <= "2015-08-10"^^xsd:dateTime) })
FILTER(NOT EXISTS {?y ns:sports.team_venue_relationship.to ?sk2} || 
EXISTS {?y ns:sports.team_venue_relationship.to ?sk3 . 
FILTER(xsd:datetime(?sk3) >= "2015-08-10"^^xsd:dateTime) })
}