There's always yet another compression scheme out there, and I just tripped across a TAR.LZ file. Never seen one before. LZH and others, but not this. http://www.nongnu.org/lzip/lzip.html
Seems to serve a purpose, though not really sure if it's not already been covered before somewhere.
But it does seem somewhat odd to distribute files like that as it adds another step when you need to download then ./configure make just to extract an archive. Oh well. I guess another compression format can't hurt.