I just spent two amazing (and very very packed!) days and nights in Paris with four friends. Unfortunately the 2hour journey there became a 4 and 1/2 hour one because our Eurostar broke so we needed to get a new one but that was really the only bad thing that happened.
I think the highlight of it for me was the night we went to a piano bar - the pianist was amazing and loved us, playing French classics along with Lady Gaga and Katy Perry and even played a jazzy version of the Spice Girls Wannabe when we requested it :) We were danced with three crazy French people (limboing, conga-ing and even robot-ing). Plus I got to sit on the piano :) So a great night and a lovely end to an amazing day.