Personally, I'd go for some non-printable characters. But, maybe I'm just nostalgic for when starting a directory name with ALT+255 rendered the directory inaccessible to Windows 9x...
Not to be secretive, but I do have an emoji domain name (.ws allows them). You can use it for email, but it's a bit of a pain to use the address in practice. It's easier to send links directly to people, but it is kind of funny to be able to use emojis to email my kids.