The BBC website has a Voices section with lots of interesting resources for language-lovers. By clicking on the coloured dots on the UK map, I discovered the existence of polari or gay slang language. You learn something new every day.
You can play at guessing which regions various accents come from. It’s a shame I can’t do the test (I haven’t plugged in my speakers to try and minimise the mess in my new “workspace”), as I’m notoriously bad at it but really enjoy trying to guess. They are also building a map of the different words used in different UK regions. It will be interesting to check the website regularly and see what sorts of things people put on there.