There are hundreds of games that kids can play on DlaDzieci.pl. Cicking on the Gry link brings up 26 pages of games from which to choose, as of August 2015.
"Dla Dzieci" is Polish for "For Children," so it can be assumed that the website's contents are safe for children. The tab Gry, which means "Games," features hundreds of Polish language flash games for children.
An example of a game that is definitely suitable for children is "Szukamy pary." It features a group of figures with varying colors and facial features. The object of the game is to find two figures that match within a given time frame. Another fun game is "Ukryty ptak." In this game, the player has to find the correct bird figure in a group of birds using a small key featured on the side. This would be a great exercise for children to practice spatial reasoning. A game similar to this would be "Matrioszki," which involves reordering matryoshka dolls according to a key of silhouettes.
These are, however, just a few suggestions out of the hundreds of games. All of the games appear to be suitable for children in terms of appropriate content and degree of fun.