I liked a lot of them. Sushi-go-round I think was my fave in Stadium 1, and I also used to pwn at any of the games that were about mashing buttons really fast, except I think Thundering Dynamo. I could not, for the life of me, be any good at the dang Clefairy game, though.
Stadium 2 had a lot more good mini-games IMO. 'The counting game', 'the Cut game', Egg Emergency, and Delibird's Delivery were my faves. Me and my brother got so crazy and competitive with them X3 He liked to spam the 'feint' thing in Eager Eevee, too, like mash it repeatedly while they went around the basket dealie.
On a side note, every new 'main series' game I got (I think starting with 3rd gen) I got a Golbat just to name it Golbony, a la Gutsy Golbat. That's how much I got a kick out of that name, I guess X3