Don't sue to have it removed. That is just what the xians want.
I think a group should first put up another plaque right next to it, with ten other biblical commandments, like about sleeping with your dead brother's wife, clean and unclean people, dietary rules, instructions for sacrifices, what to wear and so forth.
And then another one with the Five Pillars of Islam.
And then another one with nogodsforme's new and improved Ten Suggestions.
And then another one with the Prime Directive.
And then another one with the Toll House Cookie recipe.
The park will look like a grave yard, there will be so many monuments and plaques. It will be a tourist attraction and the town will charge money for people to come and see it. Win, win, win.