Gametwist started originally with in-browser flash games, have since moved on to offer all kinds of video slot machines, casino games, card games such as online poker and
online skill games. They use their own virtual currency on their site and otherwise have all the makings of a regular online casino, but their saving grace are definitely their arcade style games. Based on classics that everyone knows and has played before, they still manage to present them in their own way and do it well, sometimes even coming up with a nice spin of their own. The best of their stuff is definitely their puzzle games, they are all easy to learn but incredibly hard to master. Sugar! has to be named before all the others, since it's definitely their best one at the moment. Much like the old flash based arcade style games, their site and portfolio are perfect to play on the go, or when you are having short breaks and not much else to do.
Most sites that offer these games are just trying to reel you in and get you to gamble on their other games, but they try to keep it clean and make your speed and skill actually count. You can make enough of their site-wide currency just by running these games, and you never have to set foot in their casino area for example.
As far as
playing arcade games online and for free is concerned, these guys might be far from the first couple of places you would recommend to others, but maybe, just maybe, gametwist deserves a visit or two. They seem a solid bunch so far, and there are worse ways to kill a few minutes every now and then!