As a proposed solution to the problem of ISPs monitoring Internet traffic, one Adam Langley has devised a system of encrypting packets at the TCP level.
Obfuscated TCP uses encrypted, signed packets to make it harder for snooping middlemen to wiretap data.
The project is only in a beginning stage, with a rough implementation in the form of a Linux kernel patch plus userspace tools. The hugest hurdle, as ever, will be to gain the widespread adoption that would make it viable.
There’s a discussion of ObsTCP underway at Reddit.