favourite gameboy family games?

Lots of good suggestions already, but what first came to my mind is Final Fantasy Tactics Advance. I'm not even into Final Fantasy and have only played a few tactical RPGs, but I fell into FFTA hard when it came out. The battle system was fun, with a little twist that there's random laws you have to follow each fight (e.g. no attacking with staves) that can get a character arrested and taken out of the action after a warning. Nice music, cute art style, and a pretty good story as I recall.