CREATE TABLE table_28680377_2 (original_air_date VARCHAR, us_viewers__million_ VARCHAR)

What is the original air date of the episode that was watched by 0.88 million U.S. viewers?
SELECT original_air_date FROM table_28680377_2 WHERE us_viewers__million_ = "0.88"
SELECT "original_air_date" FROM "table_28680377_2" WHERE "0.88" = "us_viewers__million_"