It all began with this Not Invented Here comic strip, written by Paul Southworth and Unshelved's Bill Barnes and drawn by Jeff Zugale:
Instantly we were beset by requests, nay, pleadings to make this fictional barrier tape real. And we did so, with a massively successful Kickstarter campaign. We made a few extras, currently for sale here while supplies last!
Each roll consists of 250' of high-visibility yellow barrier tape with the following text repeating in black: HELPLESS LUDDITES KEEP OUT: COMPUTER REPAIR IN PROGRESS. The tape is 2" wide and 3mil thick and is not adhesive.
We've also got a matching 2"x3" magnet. It's magnetic, and therefore the perfect thing to put right on computers.
Goes great with the Not Invented Here collection Runtime Error!