Boktai: The Sun is in Your Hand
Boktai: The Sun is in Your Hand (also known as Bokura no Taiyō, literally 'Our Sun') was a popular one-of-a-kind game for the Game Boy Advance. Boktai was the first game that encouraged players to go outside by having a "solar sensor" on the game cartridge that powered most weapons, player strength, and the ability to charge your energy. Although Konami recommended it be played outside, it was possible for players to play at it from home by a window sill or use a black colored light that gave off UV solar rays.
Another unique feature of Boktai is that before a game is started, the player has to set his/her current time and time zone. The engine can then determine when the sun will rise/set, and will simulate the position of the sun inside the game. This way, the player has an advantage during the daytime because, according to legend, vampires cannot be exposed to sunlight. The game also simulates times of day by putting "birds singing" sound effects in the morning, and giving the outdoor environment a soft orange glow around sunset.