I ended up working at a call center as a temporary job, and was given a lot of responsibilities during a major transition to another location; they gave me a monthly bonus on top of the hourly pay (I'm a salaried analyst now). The company I work for would have immediately fired me for going either way with hours, and if my boss knew, they'd probably have fired him as well (huge violation of company policy. Not saying that makes you a terrible person or anything. Just relating how it can be complicated.
I also did a few business trips while I was hourly, which started out odd, but really didn't end up being that bad. I was basically filling in for my supervisor and the management structure seemed to think the return value was worth a pretty decent chunk of overtime logged.
The bonus thing was weird, because I was basically half-salaried and half hourly. Anyone else have experience with that? My income was relatively stable as long as I stayed in the 35 - 45 hour range, and even a bit outside of that, but past that I could pretty substantially alter it. I also had a really good relationship with my boss, so like any other job, if I had started working 15 hours a week they would have had a problem. My work quality and production were solid, though, and I felt secure in the position. Interesting period of time.