As discussed over in this thread, the next Highland Park Jazz Series concert with meet-up interest is on August 24th and will feature The Horn Guys. The concerts in this series are free, and take place every Sunday in August from 5:00 p.m. to 7:00 p.m.
UPDATE: Called, for both August 3rd and August 24th. Yesterday was St. Swithin's Day, and since it didn't rain I am cautiously optimistic: is there any interest in catching one of the Highland Park "Reservoir of Jazz" performances? They're free, and take place every Sunday in August from 5:00 p.m. to 7:00 p.m. [more inside]