Bring your friends to a trashcan. A public dumpster is best, but make do with what you've got.
Take something out of the trash can and choose a player. That player is your bad roommate. Accuse your bad roommate: "I cannot believe you threw this away!"
Explain, with appropriate outrage, why you cannot believe that the targeted player threw out the thing (a solo cup, an empty pill bottle, a shoe with a hole in it?).
The cup was from your first date with your dead husband.
You were going to build a tiny car out of that pill bottle.
You needed to wear that old shoe to a job interview at NASA. (They only take disheveled people seriously over there.)
Keep ranting about its importance until the bad roommate picks something else out of the trash and accuses another player of throwing away THEIR stuff.
"Look, sorry I didn't realize this stupid cup was important to you, but WHAT is my award-winning replica of a CVS receipt doing in the trash can?"
When everyone has taken a turn, say "Well we can't bring all of this stuff home." Collectively agree on one item to keep. The item wins.
Inspired by Trash Santa, which is not a game, but rather a santa puppet that my friend Dan found in the trash this weekend.
Actually, just inspired by my favorite trash-collecting friend Dan.