Add any available leaves to your table. Ask a family member or friend to grab onto one side of the table as you grab onto the opposite side. Each person must pull the table toward her body. Often this requires wiggling the table back and forth if it hasn't been pulled apart for awhile. Insert one or two leaves, depending on the length extension necessary. The table leaves will have tiny knobs on their interiors that will fit snugly into interior table holes. Make sure the leaves are in place, and press both ends of the table together again. Again, some back and forth motion may be necessary to get the tabletop back into place.
Place a card table against one end of your kitchen table if it is not long enough after adding the leaves. Find a card table of similar height to your kitchen table. Unfold the legs and lock them into place. Set the card table directly beside your kitchen table. Use a long tablecloth to cover the transition from the kitchen table to the card table. Be sure to let your guests know that they are sitting at a card table so they will be more careful with dinner plates and drinks.
As a last resort, use plywood and a sawhorse to extend your kitchen table. Put a tablecloth down on your kitchen table to protect it from scratches. Set a sawhorse out from one end of your table and lay a piece of plywood on top of it. Let one end of the plywood rest on your table and let the other end rest on the sawhorse. In order to have a flat surface, you may need to cut an inch or two off the legs of the sawhorse using a miter saw. Place another tablecloth over the entire length of the plywood and kitchen table. Again, let your guests know they are not sitting at a regular table.