Wow airlines out of Iceland has flights from the USA to Europe for less than $100. London for lunch? Not sure of the details. Have not tried yet.

I've done it a couple of times when I've found myself with an unexpected weekend off, both times on my own. Once to Hamburg and stayed in a very cheap hotel, once by train to Lincoln just because I'd been reading about in a book the week before and fancied having a look - I couldn't find a hotel, so I ended up sleeping in a park! I'd definitely do it again, it's fun to have unplanned adventures!

When every day is for fulfilment there is no need for mini breaks other than to create a counterpoint because my brain ceases to recognise that day's bounty.
Whilst the excitement of the unknown arising from the coincidence of departures bookings time of arrival and the next flight may result in some return, it is my opinion that like a worry halved a pleasure shared doubles in value or even more.
Would I do it again? Always but remember that you are no longer the person that you were and as my brother said "The day that you cease to learn is the day that you die."