The Pledge of Allegiance to the United States flag. No way.
The short version is, as Peter put it, that patriotic Americans got along fine without the pledge until 1942, and we don’t need it now. If you feel like you must make that public performance to prove your patriotism, something is wrong somewhere.
The slightly longer version is this:
First, let me be clear: I love this nation. For all its flaws and sins– and there are many– it is still in many ways great. There are freedoms I have here which are not universal– the freedom to educate my children at home, for instance, or the freedom to worship (or not) as I choose and so forth. You know ’em. But my citizenship here is temporary and secondary; we are subjects of a King. He has placed certain rulers and authorities over us, and bid us to submit to and pray for them (read here, especially the first two sections, for an excellent and nuanced treatment of the topic). But that isn’t the same as allegiance. To swear an oath of allegiance to a national identity that is not consonant with my identity as a Christian, as one loyal to and beholden to Jesus, the risen Lord of the world, is something I will not do and I will not teach my children to do it.
Now, because this is the Internet, I feel bound to ask you not to read implicit condemnation into this if you say the pledge and teach your kids to say it. Insert something about the freedom of dissent being one of the cool things about the USA here.
Now I have some work to do so we can go watch fireworks later. Happy July 4th!