Explained in title.
Do you need something that you need to take a month off work for, or something you can do in the next ten minutes with no preparation at all?
Try this free-to-play MMO RPG, Dungeon Fighter Online http://www.dfoneople.com/ . It is a pixel art based side scrolling beat-'em-up similar to If you have ever played that arcade game Dungeons and Dragons Shadows Over Mystara, it pulls its art style and action from that. (up to 4 concurrent party members can play with you)
As far as grinding is concerned, it really does not take much at all to get to max level. Each dungeon only takes around 3-8mins to beat, and the early game flies by at a reasonable pace, so it does not get too repetitive when you have 20 different classes on your account that you want to play.
See the wiki on it here http://wiki.dfo-world.com/
And when I say different, I mean it. Each of the 42 subclasses are very distinct, from grappling to summoning to anything else, this game prides itself on its PvP experience, with real e-sports teams regularly competing, as seen here a Korean tournament has just recently concluded Reddit - Dive into anything
Thus the game is more skill based, with you inputting street fighter or mortal combat motions in order to do your special moves. Knowing when to Block and move out of the way of enemy attacks is also paramount
DFO’s filesize is reasonable, and is actively updated every two weeks or so; and has very low system requirements, so it can run just fine on my 11yr old craptop. It does require Windows, no real mac or linux support. I hear that there are some bootcamp shenanigans that work though.
Never had the attention span for the fastest RPG.
If you’re feeling bored AND charitable, you can check out my new blog…one thread down under yours.
As are we all. As are we all.
(except for those who look for inspiration…) 
Get your butt outside. Play Pokemon Go or start geocaching.
What I say to my kids is: what am I, your cruise director? Your boredom is your problem. What do you like to do? Why aren’t you doing more of that? Who do you like to hang out with? Where are they? And physical activity is the best thing for a head stuck in a rut - what’s something that sounds fun?
Now get off the couch and get out of here. 'Bye!
I’ll say to to what my mom always said to me:
Spit in your shoe. Stir it up and give it to you.
mmm
Teach yourself how to cook something you love ordering at restaurants, and maybe put your own spin on it.
Learn a new language. If that’s not doable, at least pick up some key phrases.
Volunteer. Doesn’t have to be a recurring gig, though of course it would be nice if it turned out that way.
Tackle that cluttered corner or pile o’stuff.
Oh no! Don’t go there!
Masturbate to something weird
Go to the gym.
Try playing online Mafia.
Masturbate to people playing online Mafia
Masturbate *onto *people playing online Mafia.
Masturbate to online mafia porn.
Get hepped up on goofballs and run amok naked through the streets.
If you’re bored to death maybe you could binge watch Bored To Death.
Write a novel or short story. Or at least brainstorm some ideas.
Play some mindless game like Planetside 2 where you can just shoot, respawn, repeat.
Paint, draw, sculpt.
Organize your socks.
Watch some TV series.
Fix up things around your house.
Do Couch to 5k.