"Happy Monday" is when Monday is a national holiday and you get a 3-day weekend.
"Golden Week" is a week in May with several holidays. Most people get the whole week off!
"Silver Week" is like Golden Week, but doesn't happen every year.
説明が長文になって申し訳ございません。
噛み砕いてみましょう。
"Happy Monday is..." (ハッピーマンデーとは・・・)
"when Monday is a national holiday" (月曜日が祝日という時)
"and you get a 3-day weekend." (そして結果として3連休になっている。)
「旅行に行く人が多いです。」 → Many people take the opportunity to go traveling.
"Golden Week is..."
"a week in May with several holidays." (祝日が多い5月の中の一週間。)
"Most people get the whole week off." (結果として、多くの人は一週間の休みを取れる。)
"Silver Week is..."
"like Golden Week, but" (黄金週間に似たものですが・・・)
"doesn't happen every year. (毎年あるとは限らない)
"Basically... we have special names for when holidays fall together."
(簡単に言うと、祝日が連続に来る時に名付ける習慣がある。)
アメリカ合衆国 
