I basically want three people to stand on three different pressure plates. I want them to somehow all connect in a way that when they are all activated it sets off TNT. I don't want the TNT to set of with just one person.
Minecraft – be able to make a three person winners circle
minecraft-java-editionminecraft-redstone
Related Solutions
Updating answer with much more compact version
Old stuff
I hate answering my own question but I found the answer here: http://www.minecraftforum.net/viewtopic.php?f=35&t=60816 (I was searching google for a switch diagram when I found it via station selection search since it seems most people use it for minecart stations)
Here is the schematic for anyone interested in reproducing it. This particular one is great because it's only one button wide which makes it perfect for my goal. 
Here's another one that has the indicator lights on the same plane as the button but I haven't checked this one to see how it performs. 
Here's an elaborate solution involving trapping a skeleton that appears to work well. It seems that this setup could easily be changed to use a snowball/arrow dispenser instead of a skeleton, however the business of keeping it fueled, and firing at the right time would be an issue.
Best Answer
This is a really simple thing. As seen in the following screenshots, you just have to negate the pressure plate signals, then negate the combined signal and voilà, the TNT is fired off only when all are powered.
This uses the fact that the last torch will only be activated if all three previous torches are inactive - which they only are if all three pressure plates are active.