Mine is based on an R-Pi that I've got an RFID card reader hanging off, which triggers playback of music in Kodi (aka XBMC)
Here's a video demo I made ages ago of a very early version (before I learned how to capture the RFID reader prior to Kodi/XBMC grabbing it, which allowed me to eliminate the MK802 device): https://www.youtube.com/watch?v=kwyq2xqjHW0
My toddler loves it and thinks that the standard interface for playing music is to select a card from the magnetic board and swipe it against the reader.
As a special bit of fun, I've also cut open some cards and bit the RFID loop into a few of her toys. When she swipes them the appropriate theme tune plays.
I worked on the system recently to add a web interface to manage the playlists and cards, but I haven't made the code available on github yet. Though I do have a repo with the old version here: https://github.com/Fuzzwah/xbmc-rfid-music
Another option would be a Wordpress, with lax rules on posting, akin to how ludumdare.com is setup.
The plan will be to use gh-pages to allow people to submit articles (write-ups of neat dad-hacks) and then something like disqus for comments. Help welcome!