I played a lot of Locomalito games. He makes "free, traditional games" - traditional meaning they have a lot of 80s/90s arcade flair about them, and are good for short but repeated playtimes. Good challenge, too. Not to mention excellent, excellent music, almost always by Gryzor87.
I especially played Maldita Castilla, Endless Forms Most Beautiful (a PC remake of a ZX Spectrum game - from 2012!), They Came From Verminest and Gaurodan. All well worth checking out, watch the videos!
I also played a few emulated Game Gear games on the NGage: Wonder Boy 3, Donald Duck in Lucky Dime Capers and Legend of Illusion. These were fun to play a bit each day with the daughter. WB3 is a long-time favourite of mine. Couldn't get Castle of Illusion to work, sadly.
I played a ridiculous amount of OpenXCOM, which is a great reimplementation of the best game in the world - UFO: Enemy Unknown (or XCOM: UFO Defence in the States). I even contributed a few fixes to build problems on Linux.
I got a Commodore C64 for birthday, and played some stuff on it, again with the daughter. I also played a bunch of RGCD/Psytronik releases on the C64 emulator: Soulless and Assembloids most come to mind (again, both good fun with the daughter). One of these days I'm going to order a bunch of cartridges from RGCD to play on the real machine.
Also played a good bunch of FTL. And I probably forget some games. Having a Backloggery account was pretty good for making this post.
--Eino