lua-xlibs is a collection of custom-built lua libraries for various purposes.
They all run on lua 5.2.0-beta, and are released under the 'Microsoft Public License (MS-PL)'.
(Please contact me if this is a problem for anyone.)

lib-blob handles binary large objects 'blobs', which are just blocks of arbirary binary data.
lib-blob should compile on all platforms with a compliant standard C compiler.

lib-hash provides fast SHA256 hashing for blobs.
It could be extended easily to support other variants of SHA-2 or entirely different hash functions.

lib-sockets provides a very basic sockets implementation to lua.
lib-sockets requires lib-blob, and will compile on Windows.
lib-sockets might also compile on POSIX (the POSIX-specific code is there), I have never tested it, though.

lib-memcache is a thin lair over lib-sockets which provides a memcache API. It is written entirely in lua.

lib-sqlite is a nearly-complete lua binding for SQLite 3.7.7.1. It requires lib-blob.
Later versions of SQLite will probably work fine, as will some previous versions.

Binaries are currently provided for Win32 only.
Additionally, lib-sqlite requires sqlite3.dll on Windows, which you can get by compiling sqlite or via download from http://sqlite.org/download.html