Quoted: click mazes - interactive puzzles and mazes to play on-line for free

Cool logic puzzles ala sudoku.

Lots of cool stuff on puzzles. Especially battleship, one of my favorites and which I wrote a puzzle generator/solver for. There's a good program on there for playing battleship also.

Quoted: Kadon Enterprises, Inc., online store of original, award-winning puzzles and games in lasercut acrylic and wood. Play in online Puzzle Parlor, read a Journal, enjoy children's stories, coloring book, other interesting attractions and features. Annotated links to good resources.

Solve one of these and gain instant international stardom (at least within mathematical circles - what type of stardom were you thinking of?)

Interesting accessible problems by one of my favorite authors, Stan Wagon.

Laser puzzles - kinda along the lines of The Incredible Machine puzzles except deals with reflection/refracting of light rather than general physical probles.

Quoted: Math puzzles. Interactive education. A lot of math information for teachers, students and parents. Work out and enjoy mathematics. Explore unexpected connections. Even Word Problem Tutorials