I know that watch companies have crammed some really interesting features into their watches.
I'll start out with two. One on a watch that I own now, and one on a watch that I gave away.
The most unusual complication on a watch that I own now is on my Hamilton Khaki Action Sunset. It's a calculator that will give the exact time of sunset on the 15th of each month in 6 different cities: Los Angles, Nadi, Manilla, Musqat, London and Gander.
The second is on a watch that I gifted to a good friend. The Citizen Calibre 9000 has a digitally generated minute repeater.
How about you guys?