I did hear somewhere of a solitaire game being added (I forget where I heard), but I had a few more game ideas that I think would be easy to create on this site.
-Tic Tac Toe
-Sudoku
-Mahjong
Those three easy ones, and I was also thinking a color-by-number game that goes by pixels (instead of blobs to color in). Something that would be kid-friendly and fun.