Because if nobody knows where they're supposed to sit at your wedding/dinner/party, it'll be ANARCHY.
Instagram Place Cards
Your guests probably won't appreciate it if you use photos from that trip you took to New Orleans junior year. Directions here.
Source: blog.whimseybox.com
Prize Ribbon Place Cards
This could also work as an escort card (the difference is that a place card marks your seat at a table, while an escort card shows you which table to sit at; most of these ideas are totally interchangeable). Directions here.
Source: 100layercake.com
Simple Twine Place Setting
By Sweet Paul (sorry if you spend the rest of your day looking at all his stuff now).
Source: sweetpaul.typepad.com