I invented a baseball game using dice when I was 13 or 14. Twenty years later, the game is still evolving, becoming insanely complicated and strangely lifelike as the years go by. I'm not going to expain it here because it would be the equivalent of writing a post on "how my thought processes work," but I will tell you that it involves dice (preferaby five - but one would work), a vivid imagination, an 8th grade math aptitude, scouting reports and statistics for each player, and a notebook, pen and calculator. This is serious stuff.
Pros: contrary to reputation, I am pretty damn introverted and my game is a solitary endeavor that keeps my right and left brain thoroughly engaged for hours. It has also increased my baseball knowledge to super-computer status. Watching a game with me can sometimes be like sitting with a fortune-teller.
Cons: takes up a tremendous amount of my brainspace. OCD element takes over a lot; I find myself imagining playing this game at inopportune times (the movies, at work, in the shower). Enables anti-social tendencies. Gives me blisters on my writing fingers that will never heal. My mom was never pleased that her teenage son spent hours closed up in his room with five dice and a notebook, rather than drinking and driving (or studying, I guess, to be fair).
Anyway, there's my quirky confession. My comfort is that J.Kerouac invented a similar game when he was a child. He once played an entire season with a deck of cards and kept his results and supplies in a shoebox. Of course, he wasn't the sanest of us now was he?
