Boardgamearena is an online boardgame platform which allows playing with friends and other people online. They provide over 200 board and card games many also free.
Pont is an implementation of Qwirkle which works online and allows playing with other people.
Learn Regex in a playful way by solving crosswords with Regex hints.
The Yahtzee position scorer takes the currently filled out values and dice roll and suggests the likely outcome of different game moves.