Mathematica 8.0.4 Linux/UNIX w/ Keygen
Size: 1.25 GB

This is the latest and greatest Mathematica by the same folks that created the Wolfram Alpha we all know and love . (It's 32 and 64bit in the same archive)

This is a single large self-extracting shell script, downloaded straight from Wolfram's site. Via the included keygen (a windows app unfortunately, use wine) the key is generated and you can use Mathematica at full blast, indefinitely.