The Duluth Trading Company specializes in unique "longtail" shirts that help alleviate the problem and social ill of "Plumber's Crack." They've obviously invested much thought in the matter, as you can see from this schematic of the problem. But useful and practical as such shirts may be, there's simply no excuse for Plumber's Butt Playing Cards.
This article in today's NEW YORK TIMES tells us about "Street Wars," a game played in urban environments by players determined to "kill" each other. Several precedents for this game are cited in the article, but the writer misses the most important and primal one: A 1953 story by famed and beloved SF writer Robert Sheckley, titled "The Seventh Victim."
The story was later filmed as THE 10TH VICTIM. Its most famous scene: Ursula Andress using guns concealed in her bra, as seen in the second clip below.