just like the title suggests.
you basically just steal anything from the user above you, its pretty simple
Imaginations the limit here.
I've seen this forum game in another game forum and it was quite fun and creative.
and I won't be surprised if this goes degenerate on the way.
heres an example on how it goes:
User 1: [empty/game start]
User 2: I'd steal your refrigirator
User 3: Your car
User 4: your collection of memes
and so on and so forth, you may continue on from this post.