I hope this hasn't been posted already. Remember
this? You used to be able to make your own funny signs. I saw lots of good suggestions here, and someone mentioned to SAVE our posters because the site would be taken down soon. Sure enough, they changed the site so you can't add your own text. As expected, the vast majority of people creating the signs were making anti-Bush signs. Luckily, I saved several of the files I made - taken from suggestions in a previous thread.
Get your posters here.
Of course we can still use photoshop, but they made it way too easy for us. It was fun while it lasted.