Least played game on Steam?

If you mean games that have no hours like the ones I never installed & played then I have tons of those.

and my least played game is Dwarfs at 0.1 hours

killing floor is the last game I played :D

Half-Life 2: Lost Coast
0.1 hrs on record

Originally thought it would be Dark Messiah MP, but I went over my steam list once again, and found PvZ was the lowest at 6 minutes, while DM was at 7 minutes

I have too many unplayed games from bundles...

Two minutes of Galactic Arms Race + some unplayed bundle games. :P

Bought over 230 games the past 45 days... Played 3 total.

Glad to see I'm not the only one stacking up with any decent deal around (I have an excuse I was out of steam for the past 2/3 years and barely played anything).

Guess it will make it 200 more unplayed by the same time next month... Gotta love it when buying is easy as a click and you are not forced to go to any store, digital download...

Aw well, my dear fiancee won't even notice having one pair of heels less per month I guess. Huh.

Good 70% of the total I never installed, nor played ever, nor even launch, hard to point at one but I'll probably never play eets, I would even give a go to fortix or bad rats before, and I do not those own yet and hopefully (unfortunately?) might never have (needless to say I would gladly get rid of quite few titles in my library if that was ever possible, makes me feel like one click buying dead drunk in the past but I can't recall it really happens :D).

P.S : Actually just checked, played 4 games total, and stopped by 3 more a few mins, I'm not that bad, I'll just replace "girlfriend" by "fiancee" (more accurate in any case), you never know who's reading...

"Games that aren't played at all (bundle X included some useless stuff, no disk space, are there just for the total number, yadda yadda yadda) don't count."
Hm.... I think that dark messiah of m&m multi (0.5, mostly loadnings), because didn't liked it at all, also red orchestra 41-44 (0.4), played one time, for me it was enough

Still Life 2, GundeadliGne, and Waves all tie for 0.1 hours.

I couldn't get into Still Life 2 when I started it at the time. I liked the first game, so when I feel I have the patience for the story, I'll try playing that one again.

GundeadliGne kicked my butt. Said nope and haven't played since. (Which is stupid because I know bullet hell games are hard because 'hello', they're called 'bullet hell'! I still love them though.)

Waves was not what I thought it was. Glad I got it on sale and not for full price.

Home-3 minutes played

I have almost 500 games, roughly 400 of which i never played.

Of those I actually played, i have 0,1hrs on Audiosurf (i started just to get an achievement for some Steam summer/winter metagame).

Looks pretty much like 1% of my games makes for 99% of total time... wait... OMFG I AM THE 1% O_O

OP is saying stuff you haven't played AT ALL doesn't count.

Hm for me it's perhaps Nexuiz, like half an hour. I have fond memories of playing Quake ]|[ Arena not only with friends but also with bots. And dunno man perhaps I simply got too old for this stuff, I hoped Nexuiz was something I would have fun with, but it turned out to be just too damn fast for me :( Didn't know what's going on.

... OK I checked in my profile and it kinda pans out. But I saw The Coil has less, but I actually have completed this very short "art" "game" within a few minutes and, well, didn't feel like playing again :D Also Critical Mass has less because I only turned it on once for a few minutes for some puzzle on SG forum. Also Dota 2 which I only turned on spectator view for a couple minutes so SG registers I "have" it (even tho I didn't have it back then) and its filter filters it out. Aaaand LOTR Online which I only turned on to see character creation choices, pretty much.

Beat Hazard - Didn't care for it.
Cogs - Thought it was a different kind of game. Glorified slider puzzle. I loathe slider puzzles.
Worms Pinball - Played less than 10 minutes, wanted those minutes back.
1... 2... 3... Kick it - was there some fun or enjoyment to be had in there? I couldn't find it.
Zero Gear - Hey look, it's a Mario Kart like game. No wait, the AI doesn't work and there are like 2 people in the world to find in multiplayer. Good example of a missed opportunity.

That's pretty much it, disregarding the games I never even booted up, the games I just haven't had the time to play much and some games I played while offline.