Depends on the hospital. At mine, you can do a fair amount of OT if you are aggressive about it. If you are day shift and they need people to stay late and finish rooms you can pick up 3 hours of OT.

Also, there are occasional 8 hours shifts available for weekends/odd times. There's no limit for us, because they have no choice if they need people. Plus if you are taking a weekend shift, they would be paying a PRN person the same amount so it really makes no difference *who* is getting the money.