I've been busy putting together yet another widget: Card Games. This one implements a few solitaire card games - currently Klondike (classic solitaire), Monte Carlo, and Pyramid. I've also got a Freecell implementation mostly complete, and am working on Golf next.
I took care with all these games to always provide a full Undo capability, as well as a Hint function that suggests a valid (but not necessarily the best) move. The inconsistency of undo capability is always something that annoyed me with Windows solitaire and freecell.
If anybody has any particular requests for new games, let me know!