Edit: Updated yet again, hopefully with the solution to the error everyone was getting and friendlier to Mac users.
I'm not sure if I can explain this clearly, but I'll try my best.
Basically, you download the mascots (called "ghosts") and run them with a program to see them chat with each other. (Kind of like Flele, if you know what that is.)
You can read this Wikipedia page for more information!
If you're lucky, other characters like Spain, Prussia, France, and Russia will visit your desktop XD
If something is unclear, I'll try to clarify...but I'm not completely sure what to do myself, so sorry if I'm not much of a help.
If you have trouble using Crow, I think you can use any of the other "Ukagaka" programs linked to on the Wikipedia page. (I used SSP, and it worked fine.)
This may not be as interesting if you can't read Japanese...but you can still enjoy the cute characters :D
Short Introduction to the Mascots:
1. Download the mascots + program to run them (called CROW) by clicking this text: Crow同梱版 シーランド君とラトビア君.初心者パック. Run Crow.exe.
If you already have some program and just want the ghost data, click: シーランド君とラトビアちゃん.nar.
Extract (rename to .rar if you can't), and move the folder to the "ghosts" folder for whatever program you're using.
For Mac Users: There is a mac application called 偽林檎(NiseRingo) that's explained here in the comments section.
Many thanks to senorita_7 !
Official english site for NiseRingo is found here.
2. Soon after you start, Latvia asks for your name so type in what you want to be called. You also choose what sex you are (男=male, 女=female). These choices don't make a huge difference, it just makes Sealand call you (Name)-onee-chan, etc.
3. You should then update by right-clicking Sealand and choosing the third option from the top. (The blog post has a picture that points this out.)
4. Relax and watch them chat! You can set the frequency of the dialogue by double-clicking Sealand and choosing 喋り頻度,
and reset your name/sex by choosing 呼び方変更. Or try "petting" the mascots by circling your pointer on their heads to see their cute reactions XD
Q: Crow didn't work, how do you use SSP?
A: Download from the large pink box here, extract, and move the "sealand and Lat" folder inside the "ghost" folder.
It should look something like this. (Hope it's clear...)
Run ssp.exe. Right-click the default character and "Change Ghost" if Sealand doesn't come up.
(You DON'T need to download Crow if you're using SSP).
Q: How do you get rid of the satori errors?
A: Try setting your non-Unicode language to Japanese from the control panel.
If you need help, googling will give you lots of tutorials (like this page.)
Thanks to all the comments below that clarified this <3
You can also try other programs like Microsoft AppLocale.
Q: What do you do if Sealand moves outside of the screen?
A: Press Ctrl+Shift+F12.
Q: The words are all garbled!
A: Try setting your language for non-Unicode programs to Japanese, or using Microsoft AppLocale Utility.
Q: How do you get Sealand/Latvia to change clothes?
A: I think this happens at random.
Q: How to see Prussia/France?
A: Just leave the two alone, and they'll come out of nowhere. OR choose お話する after double-clicking Sealand and type in プロイセン (Prussia).
They will also respond to other country names like America, Russia, and England, but they won't appear.
Q: How to see Russia?
A: Right-click, then close the Sealand/Latvia. If you're luckly he'll appear (it's kind of scary...)
Meet Russia on shutdown 15 times and you get the option to call Belarus+something else.
Q: How to see Spain?
A: Switch back and forth from another ghost, and he'll appear at random.
Q: How to see Japan?
A: Happens at random.
Some of the interesting/fun/random things that the mascots talk about:
(this isn't a complete list by any means; S=Sealand, L=Latvia, )
S: Hey! Did you know that Sealand has an official soccer team?
L: Really? I think the soccer ball would fall into the ocean if you played in Sealand...
S: I named Denmark's team to represent me, so everything's fine!
L: Is that really ok...?
S: Sponge Bob is so cute. I want to become Sponge Bob!
L: Don't say that in America!
S: I saw the movie "Troy"!
L: The scene of the mythical Achilles' heel was very good. But after the ending, all the major characters di...
S: Aaahh stop!
S: Did you know? That France guy used to eat with his bare hands...
L: I know. It was in the 15th century...that...really was a nightmare.
S: What happened!?
S: I got a chocolate bar from France.
L: You really like chocolate bars.
S: What do you usually do, Latvia?
L: ...I work.
S: An adult!
S: America told me to watch Dora the Explorer if I'm a kid, but I think I'll go crazy if I watch that 24 hours straight!
S: Sea-kun wants to be at least as big as France some day.
L: 675,417 km2...!?
S: If (your name) likes SASHIMI, my house is best for that...
L: Lots of that is caught at my house as well.
S: Why does Latva hate Russia so much...?
L: ...I don't want to be twisted anymore...
S: What's being twisted!?
S: “Never tell a young person that anything cannot be done. God may have been waiting centuries for someone ignorant enough of the impossible to do that very thing.” –John Andrew Holmes
L: So Sea-kun is a result of that actually happening...
S: Sealand is about to be put on sale!!
L: S-sorry, I can't buy you!
S: Why does that France guy eat snails? It's scary!
L: I ate it once, and it was chewy and pretty good. But then again France-san is good at cooking in the first place...
S: I heard that adult women in Europe used to coat their faces with blood a long time ago. Is that true...?
L: That was for cosmetic purposes...it's true... Coating your face with pigeon and other things' blood used to be popular back then.
S: I want to become friends with Friedrich III.
L: He's basically harmless.
Other stuff in the blog post:
Himaruya-san apologizes for not updating the site much last year because of a heavy workload, and wants to be more active this year.
Also, he says that he will continue to add features to the mascots and try to answer more comic requests soon. :)