Games you can play with one hand?

fortix and poker night? only ones i could thing of

FTL

This may help <3

Beside porn games (as they are made knowing your hand will be busy :) ) some point-n-click games?
The Walking Dead or Wolf Among Us might be good or really bad choices, due to QTEs. Maybe some earlier Telltale games don't have them?
Some turn based strategies/RPGs (Wasteland 2, Xcom, old Fallout, Crusader Kings).

There's a few old threads about this:

http://www.steamgifts.com/forum/search/one%20hand

VVVVVV (?) but you're probably gonna hurt your other hand too, Faerie Solitaire, LYNE, EDGE, Frozen Synapse

One finger death punch. Just connect a controller and use your other hand.

Super hexagon

The impossible game.

One Finger Death Punch! You´ll love it :)

Kentucky Route Zero

Symphony can be played with one hand (mouse). But the story is nearly non-existent and it needs coordination, don't know if you can pull that off with your "untrained" hand. Other than that everything that is turn-based or has emphasize on puzzle solving. Out of my head and my library I would say:

Rush (puzzle-solving game with cubes, can be relaxing)
Toki Tori (also puzzle solving)
Underrail (turn-based rpg, interesting story start, only early access but easily 10-20 hours playtime, could be interesting if you like rpgs)
Element4I (platformer but it only needs 4 buttons, its kinda strange in its playstyle)
maybe Bit.Trip Runner (may be rage inducing)
Cthulhu saves the World (turn-based rpg)
Closure, The Swapper and Finding Teddy (all three puzzle platformers controlled with mouse)
To the Moon (story driven something)
Cherry Tree High Comedy Club

Should be enough suggestions for now.

Little Inferno, it's an ok game, and I think it's been in a Humble Bundle.

Hearthstone, MTG.

Monkey Island, if you haven't already beaten those :) The first two games are on Steam as remastered editions, not included in summer sale for some reason but they tend to be on dailies for 5-6 bucks a pack.
Maybe Burnout Paradise if you're into racing games or Divekick if you like fighting game (it uses only 2 buttons per player but it's super fun).

Robot unicorn attack games.

Monkey Island. (Story)

Brokensword 5 (Story) -would recommend, really good story. about 10 hours of gameplay.

Audiosurf (Music)

Symphony (Music)

Plague Inc. Evolved

Does "Spaff your bedsheets" count?

Civilization V

To the Moon.
U'll need second hand to wipe your tears at the end though :D

Defense Grid: The Awakening

Don't Starve, fun adventure survival one hand mouse game :)

Racing games that don't require changing gears (i.e. trackmania). Or set the gear shifting to auto for other racing games, although in my opinion, doing so takes away all the fun. Gothic I and II can also be played keyboard-only, and it's quite challenging to master the controls, but after you do so you have better control than with the mouse :D

Why don't you play first and then play afterwards? You people with two screens...

Diablo 3.. technically it can be played with only the mouse(just need a few extra buttons to bind everything to).. but its not what you need :/ .. in fact its the exact opposite.. as for keyboard only.. IDK

and eventually you would get bored and stop anyways