America's national anthem, "The Star-Spangled Banner," is difficult to sing, but it is a definite Ear Worm.
The really funny part is that the melody to "The Star-Spangled Banner" was cribbed from the theme song of an old music club, the Anacreontic Society. It is less ear-wormy in its original form, partially because "TSSB" is much more condensed.
A neat thing about "The Star Spangled Banner" that many don't realize is that the entire song is posed as a question. When it was written, the future of the country was still not a certain thing, so every time the anthem is played, it is as if you are asking for reassurance that the country has made it through each successive hardship. And when the Stars and Stripes are posted, you see that yes, it has. (The question is answered in the second verse, unfortunately most people do not know it.)
While we are on micronations, Lovely's definitely counts.
"O, Canada, our home and native land; / True patriot love in all thy sons command. / With glowing hearts we see thee rise: / The True North strong and free; / From far and wide, oh Canada, / We stand on guard for thee! / God keep our land, glorious and free! / Oh Canada, we stand on guard for thee. / Oh, Canada! we stand on guard, for, THEE!!!"
O, Canada has only been the national anthem since 1980. Before that, there were two de-facto Canadian anthems, an English and a French. O Canada was the French one, while the English one was "The Maple Leaf Forever", which may be even catchier than O Canada.
Not a national anthem, but this was the unofficial theme song for Canada's centennial year (1967) and you will NEVER be able to get it out of your head. "It's the hundredth an-ni-ver-sa-ry of Con-fe-de-ration..."
The national anthem of the Philippines. No idea what the words are, but it's so damned bouncy.
"Lupang Hinirang", "Tierra adorada", "Chosen Land". It's available in three languages; take your pick. And the "Sa dagat at bundok, sa simoy..." bit is probably the catchiest.
Filipino historians note their anthem is heavily derivative of the Spanish and French anthems and the Triumphal March from Verdi's Aida, so there's that.
The National Anthem of the Soviet Union. The one they used from '44 to '91, in all its various forms. "Soyuz nerushimiy respublik svobodnik, / Splotila naveki velikaya Rus..." There's a reason why they brought it back, albeit with different lyrics.
An interesting irony of the Cold War is that "The Star Spangled Banner" can be sung to the same tune as the Hymn of the Soviet Union, as they have the same meter.
It's even worse if you know French and watch the Gag Subversion. "KOUCHNER ALORS A MÉLANGÉ PASQUAAAAAA!!!"
Not only is the Soviet anthem an Earworm, but the Old Imperial Russian Anthem, "Bozhe Tsarya Khrani", was just as insidiously catchy. (It even shows up in Mulan, where it has NO business.) "Bozhe Tsarya Khrani" was so insidiously catchy that, until 1990, U.S. State Pennsylvania used the tune with modified lyrics for its anthem "Hail, Pennsylvania".
And before that - since the 1790s - the royal Prussian anthem (same as above, but with "Heil, König, dir!"). The text of which was based on an anthem in honour of the king of Denmark written for his German-speaking subjects in Schleswig-Holstein.
As a matter of fact, from the late 18th century on many German states had songs set to that tune, such as the one for the Free and Hanseatic City of Hamburg: "Auf Hamburgs Wohlergehn, / Lasst kein Glas müßig stehn, / Trinkt Hamburgs Wohl!" (To Hamburg's well-being, / Let no glass stand idle, / Drink Hamburg's health!).
"God Save the Queen" also has French and Maori Translations for Canada and New Zealand, respectively.
The Polish national anthem. It was written for Polish soldiers warring for freedom in Napoleon's army; being a soldiers' song meaning to raise spirits, it sounds particularly intimidating when sung by a large number of men - for instance, football fans...
Not exactly an anthem, but... the Polonez from the movie Pan Tadeusz. It's usually the opening dance on Polish high school proms.
When the anthem was chosen, the other option was this.
The beginning of the Chinese National Anthem sounds like the beginning of about...ten million songs. Which means there are ten million songs that can get it stuck in your head.
"Austraaaaalians all let uuuuuus rejoice, / For we are young and freeeeeee...."
Not the anthem but "We are one~ but we are maaaanyyyy~ / And from aaaall the lands on earth we come..." definitely qualifies.
As the closest thing to a national anthem that is not actually a national anthem in history: "Waltzing Matilda, waltzing Matilda, / You'll come a waltzing Matilda with me. / And he sang as he sat and waited 'til his billy boiled... / You'll come a-waltzing Matilda with me!"
The first one's "We are Australian", the second is about a sheep-thief who drowns himself so he doesn't get hanged. He then goes on to be a ghost..
New Zealand's one deserves a mention... "E Ihowa Atua / O nga iwi matou ra / Ata whakarangona / ... / Aotearoa // God of Nations at Thy feet / In the bonds of love we meet / Hear our voices, we entreat / ... / God defend New Zealand". Yes, the anthem is sung in both Maori and English.
The one of Italy is quite catchy. It's in an Opera-ish tone, and makes you sing along. With the slow lyrics it's a real possibility. Fratelli d'Italia~
Japan's national anthem. "Kimi ga yo wa / Chi yo ni ya chi yo ni / Sazare ishi no / Iwao to nari te / Koke no musu made." The words are from an ancient poem; the melody, written by Yoshiisa Oku and Akimori Hayashi and arranged by Franz Eckert.
Colombia's anthem is quite moving, as is Venezuela's. The first basically says "Things may be bad, but they will get better so don't give up hope", while the second tells the listener to resist oppression. What's not to like?
Mexico's national anthem — the condensed version — is fairly catchy. Do you know what's catchier? The full version. Because then it has continuity to make you remember it. (It's also fun to translate/summarize for people. "Basically, they're saying 'You guys! We should all go fight in the wars you guys! The country will love you, guys, and if we're defeated, we'll leave you the ruins so everyone in the future will just walk around saying "Those Mexicans were really badass!"'")
Apparently Mexico's national anthem is so catchy, even some stations in Southern California play it. Certain laws pertaining the Mexican National Anthem state that all Radio and TV stations should always start and end their transmissions with the anthem. And there are also a few radio stations that while they are located in border cities in the U.S. they also have Mexican callsigns, thus they are compelled by law to play it.
The Cuban National Anthem, AKA the Bayamo Song.
There is a very famous, and very earwormy, tune that is currently best known as "The Battle Hymn of the Republic", but there are many, many different lyrics set to it.
"John Brown's Body", a slightly older version, was used as a Civil War marching song. There are many small variations on the lyrics to this version, thanks to the nineteenth century version of Memetic Mutation.
Another version, titled "Blood Upon the Risers", featured in Band of Brothers, is about an unfortunate paratrooper whose parachute malfunctioned.
The Dutch national anthem, allegedly the oldest national anthem still used, is also catchy if played on a marching tune. And it is a tribute to their national hero, Prince William of Orange, rather than to their country itself.
What is more interesting is that some of the lines imply that they still respected the Spanish king, which means that the Dutch had really beef against the Spanish colonial officials, not the King or the Spaniards in general.
The North Korean anthem is epic that it outstripped the Chinese national anthem in epicness.
While it isn't precisely a national anthem, it's an anthem nonetheless: the Internationale, the international anthem of the socialist movement. The tune is stirring and incredibly catchy—even a diehard conservative will find him/herself whistling the tune after hearing it once. The best versions are in the original French and in Russian (it was the national anthem of the Soviet Union from 1917 to 1948), but really, the tune at least will get in your head no matter what language you hear it in.
Formula One fans will most likely end up having some National Anthems as Ear Worms if they watch the podium ceremony after every single race. And those anthems that really stick will be those represented by the consistently winning drivers and teams. For instance, the Michael Schumacher/Ferrari era had fans getting the German and Italian National Anthems in their heads, then when Fernando Alonso rose to the top, the Spanish National Anthem was in.
Argentina's anthem. A famous Argentine film that they show in advanced Spanish classes, La Historia Oficial, uses that for its selection screen.
Deutschland, Deutschland, über alles...
To make it clear, the German national anthem is only the third verse of the Deutschlandlied. The above phrase is from the first verse which is not part of the anthem, as its meaning was reinterpreted by the Nazis. The intent of the lyricist was that the unity of Germany (it was split up into numerous kingdoms and duchies in the 19th century) was more important than the differences between the smaller states. Sadly, after the first world war, it was used more and more by hard-rights to sing about Germany's superiority. Also, the verse mentions where the Germany the lyricist wanted was supposed be, which consisted of areas which, at the time, could have been called German or at least German-speaking. After Germany and Austria were split up politically and Germany lost Prussia (among other regions), this was no longer appropriate. The second verse is more like a drinking song, mentioning how great German women and wine are. The third verse is more fitting to the ideals Germany wanted to represent, it starting with Unity and justice and freedom. You are free to sing the first two verses, although they are not officially part of the anthem and will probably get you wierd looks from most people.
Basically any South Asian national anthem, including "Jana-Gana-Mana" from India, "Qaumi Tarana" from Pakistan, and "Amar Shonar Bangla". They use Regional Riff Instruments to play the anthems as opposed to Western ones. But the catchiest? "Milli Surood", Afghanistan. Especially the last chorus, "Wayu Allahu Akbar!"
We should note that "Jana-Gana-Mana" and "Amar Shonar Bangla" were both written by Rabindranath Tagore, the Subcontinent's greatest modern poet (he was, among other things, the first non-European to win the Nobel Prize). note Tagore was a Hindu Bengali and died before independence led to the partition of Bengal into majority-Muslim East Pakistan—later Bangladesh—and the majority-Hindu Indian state of West Bengal.