I have to give credit. A recent email from HomeMadeTools showed a tool which is used to straighten deck boards. Nice idea, but I use a different method.

Cut a scrap piece of 2x6 in a wedge. Nail another scrap a few inches from the bent board being installed. Then place one wedge cut against the bent board and the other wedge between the first wedge and the nailed scrap.

Simply use a hammer to tap the second wedge until the the board is straight. Then nail/screw the deck board in place.

As a final step, dab a little pressure treating fluid into the nail hole to ensure it remains coated.

Nearly free and only 1 nail hole.

All of my decks are done by myself so I have had to work on techniques to deal with problems.