Mine is Harry Potter.
I remember standing in a Borders packed elbow to elbow with people waiting for the seventh Harry Potter book - passing the time by leering at Slytherins and raucously singing competing/duet versions of "Weasly is Our King".
* Slytherins: "Weasly was born in a bin" Gryffindors: "He NEVER lets the Quaffle in." BOTH: WEASLY IS OUR KING!
Pottermania has recently reappeared vehemently in my life.
Here are some clear examples of Pottermania issues:
a) me being at the library and picking up a book called "Mapping the World of Harry Potter" which is a book of essays about Harry Potter written by authors of various fiction genres and people with a PHD in philosophy.
Take away: I am reading a commentary on Harry Potter. Which I enjoy. I do not regret it.
b) I drew this picture of some owls from Harry Potter.
c) Reading the Philosopher's stone and realizing that Snape's potion puzzle is LSAT puzzle diagram-able. Yay logic games. The one in the book is more open because because you cannot see the potion bottles - making the 3rd clue unfortunately useless.
I made it easy for you though.
Harry needs to go forward - which potion will take him through?
Two of us will help you, whichever you would find,
One among us seven will let you move ahead,
Another will transport the drinker back instead,
Two among our number hold only nettle wine,
Three of us are killers, waiting hidden in line.
Choose, unless you wish to stay here forevermore,
To help you in your choice, we give you these clues four:
First, however slyly the poison tries to hide
You will always find some on nettle wine’s left side;
Second, different are those who stand at either end,
But if you would move onward, neither is your friend;
Third, as you see clearly, all are different size,
Neither dwarf nor giant holds death in their insides;
Fourth, the second left and the second on the right
Are twins once you taste them, though different at first sight.
You tell me- which one is it?
d) This rant I made on facebook about a buzzfeed article.
I left it in small print just in case you didn't feel like reading it - but it is a worthwhile rant. This is the offending article: 16 Reasons You'd Probably Die at Hogwarts. It appears to me that they may have (GASP) just watched the movies without reading the books. Poor muggles. Bless them.