Anyhow, here's the second week: enjoy!
Game type: Web/flash-based, no download (except of Flash if necessary), no signup
Time demand: Varies, but undemanding. Basically time-killers for the most part, short games that don't take too very long and you can play as you like.
Cost: Free, donations accepted but not required.
What it is: A site by a Japanese Flash developer with a slowly growing collection of original games. These pretty much run the gamut from reflex-taxing games that require hand-eye coordination (well, mouse-hand anyhow) to quirky point-and-click adventure type games to at least one longer exploration game that you can save and come back to later. Basically go there, play what you like, and ignore what you don't. Some of my personal favorites from the site:
The GROW series: These are unfortunately not much in the way of replayability, at least not until you give it a couple months so you can forget the actual sequence of things. But basically the point of each is to click on the objects around the sides of the screen and drag them to the ball/cube/map/whatever in the center, so that they can take root and start to grow into different objects. The goal is to get the right sequence of items to "solve" the object, and get each of the smaller objects to their maximum growth value. Which is trickier than it sounds, as some of the objects have odd interactions for both right and wrong sequences, and you have to figure out just what you want to do.
Chronon: one of the point-and-click adventure type games, for lack of a better term. Basically you're shown a monster's house, with a person as a captive, and you have to find things around the screen to click on to cause them to... do things, and then figure out the right order to click on them. It's really really tricky, and I ended up eventually resorting to a spoiler site for the answer, just because I really wanted to see how it all came together.
Galves' Adventure: This is like Chronon in a way, but with an added level of "aww" because it was created to celebrate a friend's baby's birth, and said baby is the star of the little adventure. You have to find things to click on on the screen, and click on them in the right sequence to get cute little Galves from his starting point to the end of the game where he can defeat the lion.
Anyhow, these are some of my favorites, but there's a bit more variety there for those who don't like those particular games. Give 'em a whirl, see if there's anything that catches your fancy. Enjoy!