Distance-based Phylogeny Inference: Inferring and rendering a phylogeny using UPGMA or Neighbor Joining. Draw phylogenies starting from dissimilarity data, or directly from Newick tree notation.

Bridges Solver: Algorithmically solving a grid puzzle. This site has examples of the puzzle.

Integral Approximator: Numerically estimating a univariate definite integral given a function. Choose from a left, right, midpoint, trapezoid, or Simpson's approximation.

Connect Four: Written entirely in JavaScript so your browser can do all the work. Play against a human or a machine.

Speller: All the words from any set of letters—useful for cheating on any word-making game.