Fishing in Ocarina of Time. No scores, no time limits, no indicators or multipliers. Just sit back, chill out and fish. If you need goals, you can keep trying to catch bigger and bigger fish. I was just happy snatching the shop owner's hat. I don't even like fishing generally, so it speaks volumes how beautifully implemented it was.
The fishing in Twilight Princess was great too, the boat was a nice addition, but I still prefer the one in Ocarina slightly better.
If you can count it, Mercenaries in Resident Evil 4 was an artform of its own. I hate that minigame now, but I played it enough to get an S-rank with every character, in all four stages, which unlocks the handcannon. And you simply can't deny that it's beautifully built around the crowd control gameplay with added time limits and multipliers. I still enjoy watching crazy japanese people score hilariously high combos in the levels without missing a beat.
For instance,
Yankichi shot a 288 combo in Stage 2, scoring 332970 points. That's no longer the record though (which is 342970).
Jam it back in, in the dark.