I find that one effective method of forcing my brain to do the things I want it to do (ie, work), rather than the things it wants to do (ie write long confused posts about undocumented Cornish history, doublecheck exactly what the Ring of Barahir looked like, rashly offer to foster a coonhound, Hack All the Garden Things, and write short stories including ravens) is to tell the bloody thing that it will just have to stay up all night, and I *will not allow it to go to bed until it has done its homework*.
Eventually the damn thing knuckles under. This technique is not great for getting things done the next day, but at least I do actually get a really surprising amount of stuff *done*. I do wish my brain would be more cooperative. Sometimes it seems like the thing belongs to someone else entirely. *kicks brain*
So far I have resisted the temptation of fostering the coonhound. He looks very cute in his photos, but I think my hounds are quite enjoying being a twosome for a bit.