HunieCam Studio [Steam store page]
It seems like a lot of people like this game, but it's average at best, with the quality declining the more time you spend playing it. Basically it's a shallow clicker game, which surprised me since the store page seems to imply a bit more strategy and management.

Instead it just tries to keep you occupied clicking a handful of different buildings instead of adding any real depth. I'm sure you can optimize it slightly to get a higher score, but there aren't even semi-deep strategy or mechanics here.

As a side note, this game is tagged 'Nudity', but does not contain any as far as I can tell - unlike other games like HuniePop from the same creator.

Costume Quest 2 [Steam store page]
Better environments than CQ1, with the same great characters. The first level is the only bad part, so suffering through that small grind is worth it.

This slick looking puzzle game is simple, but enjoyable. As the game progresses you unlock six special abilities and more complex puzzles to go with them. Aside from the simple 'normal' puzzles, there are also 'hard' and 'bonus' levels.

Crayon Physics Deluxe [Steam store page]
The concept is interesting but the puzzles are super simple - though you can get extra stars (points) by finishing them in overly-complex ways. Would have been cooler if drawing shapes spawned objects like in Trine (with more variety)

Plants vs. Zombies GOTY Edition [Steam store page]
A fairly relaxing arcade game - while repetitive it can get tough on the endless levels, especially right before each of the endless achievements. Would be nice if the game remembered your choice of plants between levels

Spiral Knights [Steam store page]
The graphics are cute and the game seems potentially fun, but it lags incredibly bad on my PC - and I'm not sure if it's a problem with the game itself or their servers coping with the player load. Regardless, unplayably laggy even when moving.

Machinarium [Steam store page]
Nicely drawn point and click - but the puzzles are too obtuse for their own good. The hint button is hidden behind a long minigame with a key that shoots bullets (which the game doesn't mention and the minigame can't be completed without them)

World of Goo [Steam store page]
I'm not madly in love with this game, but it's a decent way to pass the time. The puzzles are usually fairly easy, though sometimes it is hard to execute them because of the way the AI makes goo run around the structure