Growing up, one of my favorite games was Psyche-Paths, the object of which was to create pathways of the same color using hexagonal tiles with a variety of pathway segments printed on them. Pscyhe-Paths lives on as Kadon Enterprises' Kaliko; the cardboard tiles are now wood, and the price has increased accordingly (about 100 times the original price). Now Gopherwood studios has created an online Flash game called Entanglement with many of the same characteristics (hexagonal tiles, path creation) but some key differences (a single pathway color, twice as many path segments per tile, one-tile-at-a-time gameplay). It produces paths very similar to the pattern on this Saks Fifth Avenue necktie, and it has replaced Drench as my favorite Flash game.
Correction: Entanglement does not use Flash, it's all HTML5. So it's my favorite HTML5 game, and Drench is still my favorite Flash game. Whew!