This thought did occur to me, yes. But I figured the "rational" choice - which is not actually rational, since it's predictably not going to win - of zero was doomed anyway, so chose 1 rather than guarantee a loss with 100 for no purpose.
Edit: Oh. There's nothing preventing you from voting multiple times. Hmm... in that case 49 is probably the best bet.
NPR's Planet Money is running an experiment which could be an interesting way to test your other-people-modeling skills.
This is a guessing game. To play, pick a number between 0 and 100. The goal is to pick the number that's closest to half the average of all guesses.
http://www.npr.org/blogs/money/2011/10/03/133654225/please-help-us-pick-a-number?sc=fb&cc=fp
The other people guessing are self-selected, I would assume primarily NPR listeners.