Insert a row into the table omitting all values?

Suppose I have a table with a serial as primary key and couple of other columns, that are all nullable. Is there any way to insert a new row in that table by omitting all the columns in the insert clause? Since serial is auto-incremental and can be omitted right? The rest of columns can be null and can therefore be omitted too? So theoretically it should be possible somehow. But is it?