The following are Java-based puzzles and single-player games.

Fiver

The goal is to convert all of the White pieces on the board to Black pieces.

The Towers of Hanoi

The classic puzzle, a favorite of programmers and Buddhist monks.

Peg Solitaire

The goal is to remove pegs from the board by jumping over each peg with another peg; this removes the "jumped" peg (similar to Checkers jumps).

WordSearch

Find words in the grid that are listed in the panel. Topics are animals, countries, measures, movies, nightsky.

Rubik Unbound

The famous frustrating colored cube. Twist or rotate by pointing and dragging in "natural" directions. Press s to scramble and r to restore (while positioning the mouse cursor somewhere in the applet region).

15-puzzle

15 square tiles, numbered 1..15, arranged in a 4x4 frame, with one empty space. Slide the squares around to get them in order.