A write in, or even just scrawling "FUCK YOU" across the ballot is at least an active protest. It shows that you aren't apathetic to, or okay with, what is going on. It'd be interesting to see a write in campaign for someone with enough public support to be more than just a protest vote though. It'd be interesting to see someone campaign to the public with no interest in participating in the two party system at all, just asking the public to write them in when the time comes.