My kids have been able to infect our computers with some really nasty adware and spamware by trying to install Minecraft mods.<p>One computer is a Windows7 PC with UAC disabled (unfortunately), so I had to do some deep dives into the registry to clean it. The other was a Mac with Yosemite, and that was so messed up we had to take it to the Apple Store for a wipe and reinstall.<p>I've tried to coach my kids on downloading and installing things, but when friends come over to play Minecraft it's like they forget everything.