Pectorals

Looking for a Pectoral chest workout that requirs few (if any) weights.  I have a pair of 20 lb dumbells, but no bench press etc.  Wondering if I can get a workout with them w/o going to the gym and getting a bench or a bench press.  Any thoughts?  I'm looking for bulk, but I'm assuming I can't get that w/o lifting uber heavy weights.

you cant get size without lifting heavy weights, you can only shape them with light weights.

yeah that's what I thought