Question: How many episodes were written by Gregg Mettler?
SQL: SELECT COUNT("No. in series") FROM "1-29436238-1" WHERE "Written by" = 'Gregg Mettler';

Question: What date did episode 4 in the season originally air?
SQL: SELECT "Original air date" FROM "1-29436238-1" WHERE "No. in season" = 4.0;

Question: What date did "The Big Giant Head Returns Again (Part 1)" originally air?
SQL: SELECT "Original air date" FROM "1-29436238-1" WHERE "Title" = '"The Big Giant Head Returns Again (Part 1)"';