What happened with my company: We are all salaried, we cannot get overtime pay. Usually if we work extra, we take back the time at a different part of the week. We were finishing a 12-18 months project, and our team got forced to pick up extra duties at the last minute (including testing our own software, which is really a strategic no-no in a programming environment); I ended up pulling 31 hours during my 3-day weekend over labor day, just so we could make deadline. Then I ended up just not coming to work for most of the next week and thus took back what time I could.
early in my time there, I didn't realize I could not get paid for extra hours and was charging overtime and made over $2000 over the next few months... and then when Accounting found out, they forced me to pay it back to them. I probably should have fought that (it was their fault for paying me), I didn't realize I wasn't supposed to get paid,by contract but I was much younger and unsure of myself.