Magic Calculator 2.15 - Available on the Mac App Store

Just between a scientific calculator and a spreadsheet.

Quadra Blocks 1.0 - Free

A classical arcade game, with a very hard mode (Insane mode).

Infofile 1.0 - Free

Determine the file type of an unknown file.

geoMac 0.24 - Free

Interactive geometry.

CamlX 1.6.1 - Free

Graphical interface for Caml Light or OCaml.

xVigenere 0.5b - Free

Encryption/Decryption with Vigenère cipher, an cryptanalysis to find the key of a ciphered text.