"Corrupting" a friend was a great way for me to start geocaching.
I had been doing some research on geocaching and GPS, and was getting pretty excited since it's right up my alley. I told a friend of mine about it, and that there was a cache on our campus (we go to York University). We decided to hunt it down right away instead of with a GPS (it took us three attempts, one clueless, one in the dark, and one in the rain) before we found it.
Needless to say, although we are living in different places this summer we're both buying GPSrs and we're going to see who can get the most finds before September, we're even planning a trip to go caching somewhere in the woods instead of just in the city! I'm now trying to get my summer roommate into it as well - she swears she can't even use a compass, but I bet she'll love it too!