What Shakespearean play features the line: A plague on both your houses?

Questions

Tom Petty: What year were 2 Tom Petty and the Heartbreakers albums released?

Tom Petty: Which ex-Byrd provides backing vocals on "All The Wrong Reasons"?

Tom Petty: Who is Tom refering to in the line "Me & Del were singing 'Little Runaway'"?

Top Forty Songs: Dolly Parton's biggest top 40 hit, it spent two weeks at #1?

Top Forty Songs: Fast paced hit from Grease was a hit for John Travolta & Olivia Newton-John?