Que would happen if, wenn Du open your Metafilter, finde eine message in esta lingua? No est Englando, no est Germano, no est Espano, no est keine known lingua - aber Du understande! Wat happen zo! Habe your computero eine virus catched? Habe Du sudden BSE gedeveloped? No, Du esse lezendo la neue europese lingua: de Europanto!
For a brief moment in the 1880s, Volapük^ seemed like it could be the language everyone spoke. The reform of 1931 notwithstanding, it has become the universal language no one speaks (though a few people at next week's Esperanto convention in NYC will reportedly try). It does have its own Wikipedia, the Vükiped, and there's even a a website entirely in the language. The language's bizarre appearance inspired the quasi-Cyrillic Volapuk Encoding^. You can learn the language and use it in email, or if you're daring even try to meet up with a Volapük speaker in your area. Or just appreciate this oddity that tried to build the tower of Babel .
I've been grooving on some of the music of Persone a lot lately (some full-length mp3 samples here). They're one of the most noticeable Esperanto 'rokbandoj', though by all means not the only one. I'm fond of Jomo kaj Liberecanoj (sample in Spanish, Esperanto, and French) as well. Of course, Esperanto isn't the only constructed language with some music; there apparently is a CD in Klingon (you only hear samples), and some song translations and info about a CD here, and there is also a bit of recorded music in Elvish (scroll down to "Elvish Music"). But most of it seems to be in Esperanto.