Word Square - Sudoku, but with letters and words.
Outguided - Feast your eyes on Outguided 2.0!
SudoKoi - Your next favorite pastime, like Sudoku
GuruWalk - GuruWalk is a platform to connect travelers (walkers) with local free walking tour guides (gurus), democratizing access to culture and promoting local economies, present in more than 100 countries and thousands of destinations.
UsDoku - Play real-time multiplayer Sudoku.
Hewell - Your virtual tour guide to the world