On one trip I made it to the airport and decided I wasn't ready to leave. I knew my flight was sold out so I assumed they would be looking for folks to be bumped. I volunteered at the check-in counter and lucky enough they were looking for people. I told them they could have my seat if they put me on a flight 2 days later. It must have been my lucky day as they gave it to me. I spent the next day and the following day chilling at an all inclusive.
I volunteer on every return flight and so far was only offered one more time but my travel mate didn't want to.