日付列が実際のMySQL日付列であると仮定します:
SELECT * FROM jokes WHERE date > DATE_SUB(NOW(), INTERVAL 1 DAY) ORDER BY score DESC;
SELECT * FROM jokes WHERE date > DATE_SUB(NOW(), INTERVAL 1 WEEK) ORDER BY score DESC;
SELECT * FROM jokes WHERE date > DATE_SUB(NOW(), INTERVAL 1 MONTH) ORDER BY score DESC;