Over at Life of Mrs. Reilly, there is a nice completing the square activity.

Here’s how it’ll work:  I have 7 stations set up around the room.  At each station, there will be the various algebraic steps in solving a completing-the-square problem cut apart and laminated and in random order.  Groups will rearrange the puzzle pieces in the correct order.

Everything you need to run this activity is at the link above.