For many of my woodworking projects, I use short pieces of rough-sawn stock. Some of the edges are too uneven to safely run them through my jointer to true one edge. Instead, I devised the following technique that allows me to cut one straight edge using my table saw. Start by placing the rough-sawn piece against the rip fence. Position the fence to get the best use out of the board and lock it down.
I then place a few dabs of hot glue down the face of the board closest to the fence to attach a narrow, straight-edged piece of plywood. The plywood should overlap the workpiece and ride against the fence. When the glue hardens, run the pieces through the table saw to get a perfect straight edge on the board. The dried glue scrapes off easily.