To quote GLaDOS, "It's been a long time."
While I've been away, there have been plenty of things going on in the world of open source, laser tag, etc. A quick google search showed me some recent developments that look exciting.
Skirmos is an open source laser tag game made by college students. It is based on the arduino, uses IR LED's to send tags (with a range of 500 feet according to their kickstarter page), X-bee radios to sync data, tricolor LED's for coloring the tag unit, has a screen (which seems to be their differentiator), and has a cool shell. Since it uses an arduino, it is hack-tastic for other arduino enthusiasts. I missed the initial kickstater, and will have to follow up with this in the future. Based on their website and kickstarter goals, the final product may not have all of the functionality that they state in their kickstarter video. But hey, they are building something cool, and I am supportive of building cool things.
The guys at Skirmos mention that they are working with Kevin Darrah. He's another person who has a tutorial for using those silly NRF24L01+ radios (and I say that they are silly because, while I have read their data sheet and understand how one could control them, I haven't spent the time to write a library for controlling them and don't want to. I want a free one that I can use for whatever I want. Including teaching children how to build laser tag). Kevin has a website here with some cool projects relating to LED cubes (shift registers, multiplexing, etc.) and some home automation stuff with the aforementioned radios (which turns out are really cheap on ebay). He also made a breakout board for those things. Because who wants to solder 8 pins every time they use one?
IBM developerWorks has a three part tutorial on building laser tag. Who knew? I had some trouble navigating from part 1 to part 2 (there wasn't a link from part 1 to part 2 that I found faster than googling for part 2, so I'm posting the links to all 3 parts). I may have to look at developerWorks from IBM for more cool projects.