A RTC board updated via a WWVB receiver (or the chips to diy) would be great.
Any “self-setting” clock radio must contain a complete WWVB receiver and antenna. Here’s an excellent webpage illustrating in detail how to dissect a Sony self-setting clock radio and remove the WWVB receiver, with pictures of the output of the receiver, http://leapsecond.com/pages/sony-wwvb/.
I’ve seen Sony self-setting clock radios for as little as $10 in Walmart. SparkFun would be hard-pressed to sell a complete receiver (chip, antenna and breakout board) for less.
Sometimes, though, it’s not about price. I have an amplified antenna on top of my tv with a built in clock that’s worthless. I would gladly hack/redesign the clock so it keeps accurate time since I can’t use the clock is the way it is now.
A crude AM 60kHz receiver would not be expensive to make however. The signal is a low datarate PWM code on the carrier.
WWVB is designed for simple implementation 
dana:
…I’ve seen Sony self-setting clock radios for as little as $10 in Walmart. SparkFun would be hard-pressed to sell a complete receiver (chip, antenna and breakout board) for less.
A complete breakout board/ferrite antenna/60 khz receiver unit is available from Digi-Key for $10.71:
http://search.digikey.com/scripts/DkSea … 61-1014-ND
They are also available in 40khz and 77.5khz versions. The November 2008 issue of Circuit Cellar has an article describing a time server using this chip - datasheet and link to the article are available from C-Max.
Got the parts, so will try this next (after I finish my speed-bag project).
I’ve designed and built a WWVB receiver module decoder using the C Max module available from DigiKey.
It also outputs ISO 8601 format serial time data.