A blazer and jeans is just about the official uniform for stand-up comics with a modicum of success, and to guarantee you keep bringing down the house once you've made it, the folks at Adafruit have put together a tutorial showing you how to make a jacket with a built-in laugh track (and other useful sound effects).
Buttons hidden beneath the jacket's lapel and inside the front pocket can be used to trigger pre-loaded sound files, which are played over speakers that remain equally out of sight. And if a laugh track isn't what you need, you can upload anything from over-the-top flatulence sounds, to chirping crickets that help drive home the deafening silence from an unamused audience.
The project is of course completely centred around Adafruit's Audio FX Sound Board, which can be purchased from the site for $US20 to $US25 depending on how much on-board storage you want. The other components can be collected from other sources if you want to shop around, and it goes without saying that basic soldering and electronics skills are a must here. But what isn't needed is the ability to convincingly deliver a punchline. [Adafruit via Laughing Squid]