Actually a smørrebrødsbord (Danish for smörgåsbord) can be as simple or elaborate as you want to make it. It just means an (open-faced) sandwich table. The bread is usually really heavy/dense rye bread in 2mm (slightly more than 1/16 ") slices and/or crisp rye bread, e.g., Rye Crisp, Wasa, Ryvita. The bread, spreads, garnishes, fish, hard boiled eggs, cheeses, etc. are all put on the table and everyone makes their own sammies. To be authentically Scandinavian, you start with fish, then on to the meat, and finish with the cheeses. Eggs and vegis are eaten any time, but are often used as a palate cleanser between the fish and meat or between the meat and the cheese.
This is the heavy rye bread I'm talking about. Looks like they started with a 1 kg (2.2 lbs) loaf: