BASEketball - Who would come up with the concept of mixing baseball with basketball to create a silly hybrid sport? The wacky creators of South Park and The Book of Mormon, Trey Parker and Matt Stone, that's who. The best part is the trash talking, which is a vital part of the competition.
Blood Bowl - Fantasy Football has a whole new meaning when you add goblins, trolls, orcs, dwarves, elves, and other creatures to the game. Heads literally roll, limbs are torn from opponents, it's a bloody good time. It began as a roleplaying boardgame and evolved into an addictive video game that spawned a number of rip-offs. Send in the trolls!
Calvinball - Calvin and Hobbes was one of my favorite comic strips because the imaginary adventures of a little boy and his stuffed tiger were not only hilarious, but at times heartwarming as well. Calvin made up a complex game whose rules were always changing. It reminded me of all the games I used to invent with my sisters, cousins, and friends when we were kids.
Death Race - A deadly transcontinental road race -- sounds frighteningly awesome, doesn't it? The cult movie Death Race 2000 (produced by Roger Corman) starred David Carradine, Sylvester Stallone, and Simone Griffeth, and the remake, directed by Paul W.S. Anderson, starred Jason Stathem and Ian McShane. A guilty pleasure at its best.
Lightcycle Race - Who can watch TRON or TRON Legacy and not feel the need for computer-generated speed? A two-dimensional old-school video game becomes a three-dimensional cyber-contest when a "real world" player becomes transported into the Digital World and the action becomes all too real.
Podrace - The Star Wars prequels had their flaws, but the podracing sequence in The Phantom Menace was adrenalin-fueled and makes me wish it was more integral to the plot.
Quidditch - Kudos to J.K. Rowling for creating an interesting aerial sport that worked really well in her Harry Potter books and movies. Unless you're a preschooler, though, don't hop on a broom and try to play it in real life -- you'll just end up looking ridiculous.
Robot Boxing - What do you get when you blend giant robots and fisticuffs? Real Steel, starring Hugh Jackman. It's like Robo-Rocky.
Rollerball - It's like extreme roller derby, no holds barred. Check out the first movie by Norman Jewison based on the short story by William Harrison and starring James Caan. The remake was directed by John McTiernan and starred Chris Klein, Jean Reno, LL Cool J, and Rebecca Romijn.
Running Man - Stephen King's original idea about a televised game show, in which contestants are hunted to the death, might sound farfetched, but as reality shows continue to become more and more shameless, the grim future doesn't seem all that unrealistic. The movie version featured Arnold Schwarzenegger, Richard Dawson, Maria Conchita Alonso, Yaphet Cotto, and Jesse Ventura. The current bestselling book series, The Hunger Games, owes a lot to King's novel.
There are others -- the very physical Pyramid from the reimagined Battlestar Galactica and the brutal fight-to-the-death Mortal Kombat from the popular video game series, just to name two. If there are any others that you can think of, let me know.