I know quite well where Maremagnum is. I only have to grab a new Metro map once I arrive in Barcelona (I've left mine in Italy).

For people who don't know how to get there I suggest them to reach Plaza Catalunya, take a walk for all the "ramblas" untill the Colombo statue. Looking at the sea, on the left you'll see a modern bridge that take you to a modern building, called Maremagnum.

My train will arrive at 18:00 more or less at Barcelona Sans station. I'll take the metro to Cornella to make the checkin at the hotel, I'll leave my baggage, my PC and I'll try to reach you at Maremagnum.

p.s: send me a private message if you want my number, I only have the number of Alberto Garcia and Aniello Del Sorbo at the moment.