try
SELECT T1.CityName, T2.EventStart, T2.EventDescription FROM Table1 T1, Table2 T2 WHERE
T1.CityID = T2.CityID AND T2.EventStart > NOW()
ORDER BY T1.CityName ASC, T2.EventStart ASC
EDIT - согласно комментарию
SELECT
T1.CityName,
T2.EventStart,
T2.EventDescription
FROM Table1 T1
INNER JOIN Table2 T2 ON T1.CityID = T2.CityID
WHERE T2.EventStart > NOW()
ORDER BY T1.CityName ASC, T2.EventStart ASC