The longest active hitting streak thru this year's All-star Break is 14 games, by OAK Athletic Shannon Stewart.  Since they moved to Oakland, the A's have had only four 20+ game hitting streaks:

G	FIRST	LAST	YEAR
24	Carney	Lansford	1984
25	Jason	Giambi	1997
24	Miguel	Tejada	2002
22	Eric	Byrnes	2003

....but they had over twenty hitting streaks of 20+ games during their time in Philadelphia.  The longest being:

29 games: Bill Lamar, 5/30(G2)-6/29/1925. 60-for-126 (.476 AVG), 10 doubles, 2 triples, 0 homers (.587 SLG).

And just for fun, the longest hitting streak ever by a player whose last name starts with 'S' was 41 games by George Sisler in 1922 (so Stewart has quite a ways to go to beat that).  Sisler had seven separate 20+ game hitting streaks in his career, which puts him near the top of this list:

Most 20+ game hitting streaks in a career
8-Willie Keeler (longest was 45 games)
8-Ty Cobb (longest was 40 games)
8-Pete Rose (longest was 44 games)
7-George Sisler (longest was 41 games)
6-Pete Browning (longest was 26 games)
6-Hack Wilson (longest was 27 games)
6-Ichiro Suzuki (longest was 25 games)


A Century of Cobb
Ty Cobb's batting line from 100 years ago:
Cobb did not play on July 11, 1907.