Llanfair and ChargoggagoggI found this amusing. The longest place domain in the world, according to someone at NamePros.com, seems to be llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch.com. According to the site, it translates to "The church of St. Mary in the hollow of white hazel trees near the rapid whirlpool by St. Tysilio's of the red cave." Wow, what a mouthful. And how about the Nipmuc name for Webster Lake in Webster, Massachusetts: Chargoggagoggmanchauggagoggchaubunagungamaugg? According to Wikipedia, it may be the longest place name in the United States and is said to mean "Fishing Place at the Boundaries - Neutral Meeting Grounds." I heard about this one a few years ago and, amazingly, remembered how it was spelled.
Update, 10/11/11: You would think there couldn't be a place name longer and more complicated than those, but you would be wrong. I just learned from @AnneMWatts (fellow follower of @TwoPaddocks, aka Sam Neill) that New Zealand has the longest place name with Taumatawhakatangihangakoauauo-tamateaturipukakapikimaungahoronukupokaiwhenuakitanatahu, which you can see and learn more about here.
If you want to learn about more of the longest things try thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com. According to them the longest place name is actually the official name of Bangkok: Krungthepmahanakornamornratanakosinmahin-tarayutthayamahadilokphopnopparatrajathaniburiromudomrajaniwesmahasatharnamornphimarnavatarn-sathitsakkattiyavisanukamprasit.
There's quite a bit of other interesting stuff, such as -
longest corn maze: 15 miles, Liberty, Missouri
longest abbreviation: NIIOMTPLABOPARMBETZHELBETRABSBOMONIMONKONOTDTEKHSTROMONT
longest movie title:Night of the Day of the Dawn of the Son of the Bride of the Return of the Revenge of the Terror of the Attack of the Evil, Mutant, Alien, Flesh Eating, Hellbound, Zombified Living Dead Part 2: In Shocking 2-D
You could get lost here for a quite a while. Have fun, and stay out of that corn maze.