by DangerousTim @ instructables.com:
That moment you take your eyes off the TV remote for just a second, because of which it falls into the hands of your annoying sibling. Yes, fighting for control over the TV is a daily struggle for many. But the TV Remote Jammer shown in this Instructable, will make everyone else stop dead in their tracks.
This Remote Jammer circuit, in the disguise of an inconspicuous TicTac Box, sends a constant signal to the TV receiver that interferes with the signal from the TV remote. This means that when the Jammer is on, your TV remote CANNOT be used to change channels. It practically blocks all signals from the remote.
Tic-Tac TV Remote Jammer – [Link]