Horribly slow speeds, but only from around 10:30pm - 1am?

I've experienced this problem before, though it was close to a year ago. It started and then stopped all on its own, so I thought the problem was fixed. Now it's back again.

For the past few nights, from between the hours of 10:30pm and 1am, my speed plummets down to between 2Mbps and 4Mbps. The package I pay for advertises speeds up to 30Mbps, and I generally get somewhere between 25-28Mbps on a regular basis. Just not during those specific times. 

It's extremely frustrating to me, especially since that's my prime time for online gaming activities. The last time this happened, it was suggested that a tech be sent out. I asked if a tech would be willing to actually monitor the line at those hours, since you know, that's when it actually happens, and was of course told that no, they would come out during normal business hours. When the connection is fine. Obviously, not much of a help there.

Is this a common issue? Is there work being done in my area? (Greater New Orleans area, Westbank, Algiers) Is some idiot overloading a torrent service and jacking up the node in my area? Is there anything I can do so I can play my game that I pay for monthly, with the internet connection I pay for monthly? I'm at a loss here, I really am.