Ride my bike. Winter sucks.
I do a lot of the things that others have mentioned: listen to music, get out and go for a walk (especially through the woods or along the shore), clean the place up as thoroughly as I can.
If it’s long term I wake up and get as much accomplished as I possibly can before noon.
Sometimes I make a gratitude list in my head. I have to give credit to Randy Blythe for the concept, but it’s exactly what it sounds like, a list of things I’m grateful for. It’s usually simple stuff, like “I have a job, I’m not in jail, I have delicious beer in the fridge, I have a home, no one is actively trying to kill me,” etc. It helps me focus on the positives.
Ride my horse in the forest. Or hike with the dogs.
Beer. Lotsa beer. 
Listen to the soundtrack to La La Land.
Or watch Singin’ in the Rain again.
Shit, Girl! You wouldn’t even leave the house for a DBT concert! 
***Waaaay ***too late to edit, but here it is:
I don’t know if the OP is a drinker, but I am. In fact, I’m pouring myself another drink of rum as I type this. Also drinking that rum. Anyway, if I’m feeling real down I have a sober week. It’s just what it sounds like, seven days of sobriety. It helps. Don’t get me wrong, it sucks, but it’s worth it, for me at least. It helps me focus my mind on the real problems and reminds me that I can do anything I set my mind to.
Collapse to the floor and wait for dog to come lick my face.
Normally I’d say food, except I’ve been on a low-carb diet, and all the cravings I have are for high-carb foods.
So it’s music, specifically Rachmaninoff, Tchaikovsky or Emmerich Kalman. Possibly a “Golden Age” musical soundtrack, like Rogers & Hammerstein.
Don’t watch the news!
That would be my gf’s answer. If she disappears for a while along with a horse and/or the dogs, I ask if everything is ok when she returns.
Redecorate the house
Do the gardening
Go to the gym
Take myself and my wife out for a long boozy lunch in our favourite tapas bar
Take the dog for a long walk on the beach
Fly to Italy
Find the thing that’s bothering me, and face it head on - tackle it and it’s never as bad as avoiding it
If I’m at work, I watch the koalas on the San Diego Zoo’s koala cam. If I’m lucky, I’ll catch them during the 20 minute window when they actually do something.
We also have a large lake nearby with a walking trail so if the weather isn’t Hellish, I can get a little exercise and hang out with the birds and the gators.
At home, I mostly work in my yard or do some craft projects.
Also, wine and a good movie, though that’s more escaping than cheering, but whatever works.
If you get lost, listen to the music play (and) roll away the dew.