(You can change the width and height in the very last line of code to fit your site better.)
<iframe src="https://calendar.google.com/calendar/embed?height=600&wkst=2&bgcolor=%23FFFFFF&src=usa__en%40holiday.calendar.google.com&color=%23691426&src=ldo2u07dpif4arsnahl9nqdavo%40group.calendar.google.com&color=%231B887A&src=bm35nbr382tr2k1ujf4aluaie8%40group.calendar.google.com&color=%232952A3&src=dfn9ha02m6tqr3tuf3g4nusfjs%40group.calendar.google.com&color=%238D6F47&src=37ahi1ll5kf9ao29g98djv9ovo%40group.calendar.google.com&color=%2328754E&src=p16obpid7t6i84rviigq0p1lp8%40group.calendar.google.com&color=%2328754E&src=8k239ls6d2tse5g5ttusbh50qk%40group.calendar.google.com&color=%23691426&src=ht3jlfaac5lfd6263ulfh4tql8%40group.calendar.google.com&color=%2329527A&src=vh341se8ujkommidn9u0dkv4fs%40group.calendar.google.com&color=%23AB8B00&src=6eftrh62ags24pe0ns1a5l7878%40group.calendar.google.com&color=%23B1440E&ctz=America%2FPhoenix" style="border-width:0" width="800" height="600" frameborder="0" scrolling="no"></iframe>
