Garmin have beat us to it!
There is a tiny little geocache device available, compatible wioth certain models of GPS receiver, that beacons a very low power ID and hint signal. The device/system is called 'chirp'. Im not sure the frequency it operates on, but i suspect its a bluetooth device. Its programmed by the cache owner, and those cachers with suitable receivers can use it to help lcoate the cache once within range, range is a few tens of meters i think.
However, although the beacon is cheap (about £20), it does require a fairly high end GPS receiver. Most of us dont have those yet. I myself am a geocacher (cache owner as well) and use a cheap 2nd hand Etrex H receiver.
BYUs concern about available frequencies is valid, especially with 80m beacons (which i use/find). But a geocache event (multiple caches and cachers together ona day) combined with ARDF would be good. Perhaps widely spaced 80m beacons, taking you into the area of a number of geocaches?
You say youve never Geocached, nor foxhunted? Both are great fun. I would recommend you try geocaching, all you need to know can be found here www.geocaching.com
and if you look up user 'Flyingcompass' then thats me! Buy yourself a 2nd hand GPS, the Garmin Etrex H is ideal and can be found very low cost. Im a keen walker and finding these has added a bit extra to my walks, and my son loves it.
After youve done that, get involved in a foxhunt! There normally a bit more energetic though!