Outsourcing the real answer
I still did not see people using this thing here in serious answers (just in some jokes ones), but already saw it being used seriously elsewhere. To circumvent restrictions and rules in the question (normally size), the answerer writes a small program that downloads the real program from elsewhere and then compiles and runs it.
A variant of this is posting an answer that takes input from the user and then submits it to somewhere on the Internet that is responsible for solving the problem and send back the output.
