My new Foxtrotter wants to go fast coming home. I call it barn-sour!
I mostly do what kevinshorses suggested, pull her down to the speed I want and then give her a slack rein, then repeat if she speeds up. She is doing really well now!
A few weeks back though, when I couldn't keep her ridden enough due to the weather, she would be so excitable going home that I had to do the circling thing, weaving in and out of bushes, etc. just to work some energy off of her.
So all three of those methods (circling, going away from home, pull and release) work pretty well depending on how hyper the horse is. If she's really bad, then we go away from home and work up and down hills and around bushes until she listens and I work off some energy. (I think the circling is more for working off energy than slowing the horse down.)
Then when she is calmed down to a dull roar, I turn for home again and try the "slow to the correct speed and release" method. What's funny about that is she will sometimes get excited and walk REALLY fast, but as long as it is a walk I give her loose rein.
I tell her she can go as fast as she wants, as long as it is a walk.
Some rides I felt like I never got her calmed down where I wanted her to be, but usually the next day riding is uneventful, so I think the main cure is keeping them exercised. If they sit for weeks, well, it's almost like they can't help themselves.