Music. Mostly heavy metal of various sorts. Everything from 80's glam metal - Motley Crue, Poison, Whitesnake, Ratt, etc. to thrash metal - Testament, Slayer, Exodus, Megadeth, Overkill, etc., to other heavy shit like Fleshgod Apocalypse, Emperor, Dimmu Borgir, Septic Flesh, Iced Earth, Blind Guardian, Sepultura, Stratovarious, Kamelot, etc., etc.
Mix in a little bit of Eminem, Dr. Dre, Snoop Dogg, etc. for a change of pace, and just jam out. That's one of my key strategies.
The other is to draw a hot bath, and just lay in the tub soaking and reading a book for a nice long time.
Regardless of how the day went I ask myself what could I have done to make the day better & jot mental notes. Then, I take a hot shower to officially transition into another mode. Compartmentalizing the emotions of the day & transitioning are very important, especially if you have a partner/family/etc.
Exercise, and if your into math, work on an interesting math problem!
1. Do something constructive:
Clean the dishes, do the laundry, or vacuum.
2. Do something destructive:
Play a video game, break an egg and cook an omlette.
3. Do something connective:
Talk to a friend, call a relative, or join a chat room.