The loser takes a full, genuine 20-minute nap in a furniture store display bed, shoes off, covers optional, while a leaguemate films the staff's response from the next aisle. Getting woken up by an associate is the finish line. Politely leaving when asked is required; this is shame, not trespassing.
Budget note: this one costs nothing but dignity, which makes it a strong pick for leagues that would rather spend the pot on the champion than on the loser's downfall.
Seen in the wild: fantasypunishments.com