Well, I'm pretty sure that "experience an earthquake" wasn't on my "things to do before you die" list, but at about 1 AM I heard a loud thud (which I hope isn't going to turn out to be bad news, so far I haven't spotted anything broken or any damage to the house) and the room shook three or four times - I think the main thing shaking was my desk, which is a little wobbly anyway. Since I live next to a main railway line I assumed it was a train revving its engines, which has a similar effect though with higher frequency. But then I realised I couldn't hear a train, so I chalked it up as traffic or something until I heard the news this morning, and discovered that there had been a 5.3 magnitude earthquake about 120 miles north of me.
It's a shame I didn't know last night, I could have panicked properly then. But never mind...
http://news.bbc.co.uk/1/hi/england/7266136.stm has full details, but it seems to have been fairly boring as earthquakes go; more intense than usual for the UK, but so far nobody seems to have been killed and only one person injured, so it could have been one hell of a lot worse.