Well, if you are in Spain - you can't go home without a couple of days in Barcelona. My favourite European city by a long shot. Madrid is ok, but Barca is great.
What are you into? Nightlife, galleries museums, architecture? Paris and London are also 2 great destinations. or you could head further north to Germany. It really depends what you are looking for. And how far from Spain you are willing to travel.
Feb isn't really a great month for weather over here - its still pretty cold and high likelihood of rain. But you could get lucky.
And congratulations on the award!