Taiko no tatsujin!!!
One of my favorite arcade games in Japan, it's essentially a rhythm music game except you get to wield drum sticks as big around as hot dogs and pound away on an oversized drum. It's a blast and the psychedelic animations that adorn the screen as you play just add to the experience. To be fair, Japanese arcades, often located near or on the top floor of multi-level shopping and entertainment centers, are pretty trippy on their own.
