I tried some of the "tame games" at yahoo.com and a few I had seen while answering a reference question at the AARP website (see link.) Already addicted to crossword puzzles until my hand is sometimes aching, I tried an online crossword. Easier on the hands, but harder to jump around and scan the clues. I did like the accolades at the end. I also tried a jigsaw puzzle and found it disconcerting not to be able to feel the puzzle or have to switch the pieces. Still, I just wanted to keep going and the spatial section of my brain needs all the help it can get. I also found the flashing advertising icons distracting. The AARP is nice and simple, although many of the activities seem the same as at the Prime Games.
As a former teacher and childrens' librarian, I was curious about the link at Prime Games that said it had curriculum related materials. I browsed Holidays and selected Hanukkah. http://www.primarygames.com/holidays/hanukkah/games.htm. The games don't actually teach or reinforce, but have the graphics to match the holiday. I think reading the New York Times article posted by e.f. about the online literacy debate shows us that web content could indeed be literacy or subject related. Maybe as librarians we need to find more of the good stuff.