Here’s a prank-style kit from MadLab Electronics, the IR-ritator. Schematic included –
A practical joke for playing on anybody who uses an infrared remote to control electrical equipment such as a television. The IR-ritator can jam a remote control and make it seem unreliable, and it can also record and mimic a remote control and disrupt the normal operation of a piece of equipment.
The IR-ritator – Link.