The battery-powered Vent-Miser features a clock that opens and closes the vents at programmable intervals, completely independent of your thermostat's settings. So if your A/C doesn't need to keep your guest room cool on weekdays or if you only need to heat your bedroom at night, the Vent-Miser can automate this process for you, possibly saving you a few bucks in the process.

At about $25 a pop, the vents definitely lean towards investment rather than instant payoff, but they're a neat idea if you live in a house with crummy HVAC. [Amazon via OhGizmo!]

Some MacBook computers may appear to be running too warm, with the fan running consistently and heat emanating from the top and/or the bottom of the computer.

If this happens with your MacBook, check the rear vent of the MacBook to make sure it's not blocked.

Some MacBooks may have left the factory with a thin piece of clear plastic covering the rear vent. This is used in the factory to prevent dust from getting into your computer. If your MacBook has the plastic still over the vent, simply remove and discard it.

– Jason Chen

MacBook may run warm because rear vent is blocked [Apple - Thanks Jonathan San Francisco!]