Buenos Aires

I have a day to kill in Buenos Aires. Misunderstood the itinerary for the tour and booked my plane ticket to arrive a day earlier than I needed. At least it's not a day later. Knowing me, it wouldn't be something unheard of. Anyone have any suggestions on what I should do? I done the major site already. I'm thinking of hitting the street fair/flea market. I think it's in San Telmo. Other than that, I'm not sure what I should do. I was thinking of going to Colonia but I don't know how long that ferry ride takes. Anyone have any friends out there willing to hang out for one day?