The silicon messiah. Iodine. Iodine Latest (from 2014-06-16): 0.7.0 Download source / binaries: win32/64, android Older downloads available below. iodine lets you tunnel IPv4 data through a DNS server.
This can be usable in different situations where internet access is firewalled, but DNS queries are allowed. It runs on Linux, Mac OS X, FreeBSD, NetBSD, OpenBSD and Windows and needs a TUN/TAP device.