Of course you may steal it. I stole it from Toronto a couple of years ago.
The trivia bingo idea I got from California Browncoats. The first year we did all Firefly trivia with five categories: people, places, actions, object and animal. I made Bingo cards with five columns and five rows. One of our committee members put all the answers on the cards then sent them to me to print (4 on an 8 1/2 x 11 card stock). The questions & answers were put into squares - one page per categor - which I then cut up. On the event day, Jedisix pulled a square out of the container, read the question twice - and usually made an appropriate comment - and then gave it to one of our other committee members who wrote the answer under the correct category so that we could check the winners. Apparently we made the questions quite hard because it took a long time to get a winner and the two of us who had come up with most of the questions then had to play "Jeopardy" with the audience as they asked what some of the questions were that they had answers to on their cards! (We also did blackout bingo the first time.)
Last year I suggested we do the categories as Whedon shows, so we did five columns again: Firefly/Serenity, Dr. Horrible, Buffy, Angel and Dollhouse. Instead of blackout, we did two lines in any direction and the game went faster. I think we'll do the same thing this year. We made 200 cards and sold them for a quarter each. They sold out within the first hour. This year we're going to charge $1 each.
The most time-consuming part is staggering the answers on the cards so that there are few duplicates.
Have fun with it.