The Puzzle Files
With its flagship contest, Labyrinth, receiving rightfully rave reviews from the puzzling community, this new contest site created by a good friend of Puzzletome (SparkPlug) has breathed life back into the sequential puzzle genre. Not to be missed!
Had To Play On
The site offers a number of varied puzzle contests and games, and also has an associated forum, where you'll find things such as the weekly contest.
Not a riddle site as such, but a forum containing discussions on many topics (including some of the puzzle contests mentioned on this page).
A traditional sequential contest with some very cleverly written and displayed puzzles. A second contest is in the works.
Planetarium runs in twelve weekly instalments starting from
the time you first log in, with three puzzles in each instalment. The
solutions to the puzzles themselves form an overall puzzle which is not
explicitly described anywhere within Planetarium. At the end of the
twelfth week you're shown all the solutions with illustrated
BizFantast (short for Bizzarrie Fantast apparently!) is a story-based series of puzzles that is ever-growing. At the time of writing, there are 72 puzzles available with more being added all the time.
The Riddle Contest
Riddle Planet resurrected -- if you're a fan of riddles, you'll find no shortage of brain-twisting wordplay here!