mxCrypto is an extension package that provides OO-style access to the cipher algorithms and hash functions included in OpenSSL/SSLeay, a very nifty cryptographic library originally written by Eric Young and now maintained by the OpenSSL team. Its main purpose is filling in the missing parts in Andrew Kuchling's pycrypt export package with high quality implementations. Due to the ITAR export restrictions on cryptographic software, Andrew's implementations are not legally downloadable from outside the US.
Scapy is a powerful interactive packet manipulation tool, packet generator, network scanner, network discovery tool, and packet sniffer. It provides classes to interactively create packets or sets of packets, manipulate them, send them over the wire, sniff other packets from the wire, match answers and replies, and more. Interaction is provided by the Python interpreter, so Python programming structures can be used (such as variables, loops, and functions). Report modules are possible and easy to make. It is intended to do about the same things as ttlscan, nmap, hping, queso, p0f, xprobe, arping, arp-sk, arpspoof, firewalk, irpas, tethereal, tcpdump, etc.
Are You Human? is a script that uses a graphical test to insure that a human is being dealt with rather than a script. This is useful to avoid automated Web signups or automated attempts to crack passwords. There are many equivalent libraries for other languages but this is the first one for Python. The Python Imaging Library (PIL) is required.