From my experience, the most fun ones are those that have all three:
a.) showing locations that are important to the character b.) something that encourages exploration c.) imagery that fits the character's motif d.) lots of things to mess with
Special items, or simple clues that leads to more info about the character without it just being another memory event is also fun. Basically, play around with less obvious indicators, and let people learn about the character by opening boxes, drawers, making art, erasing things, etc. Some people have done theater-like heart games but personally it's not my jam because your character doesn't do anything but react. Interactivity is what makes hearts game fun.
Re: GENERAL DWRP QUESTIONS
a.) showing locations that are important to the character
b.) something that encourages exploration
c.) imagery that fits the character's motif
d.) lots of things to mess with
Special items, or simple clues that leads to more info about the character without it just being another memory event is also fun. Basically, play around with less obvious indicators, and let people learn about the character by opening boxes, drawers, making art, erasing things, etc. Some people have done theater-like heart games but personally it's not my jam because your character doesn't do anything but react. Interactivity is what makes hearts game fun.