I thought it would be cool to have my own TLD, but apparently it's all managed by the ICANN, so you can't just name your website with any TLD you want. There are different prices. But at least you can customize your second level domain. Why aren't TLDs like this?
At least in windows, the hosts file can point from any domain to any IP. In theory you can do things like point advertising domains to 127.0.0.1 if you wanted to make sure web requests never made it off your local machine. I did this a lot back in the day to test websites running locally but pointed to a friendlier name than localhost:randomport