ask to be bumped

Here's one that I used to pull ALL the time when I travelled for work. Whenever I flew, I'd make sure to go to the gate and ask that my name be added as a volunteer to be bumped. If I did get bumped, the airline would typically provide me with a free travel ticket or a voucher good for a certain dollar figure. Of course, I'd make sure to reserve a flight that had at least one more flight going after mine to my destination. By doing this, I managed to get several free travel vouchers, and I'd still get home on the same day.