Guess what episode the quote is from.
If you don't know, you can ask for a clue. You can be specific [ie: What season is it from?] or you can just ask for a general clue. Clues are unlimited, you can keep asking until someone guesses right.
Whoever guesses the right episode posts the next quote.
Everyone who participates must check the forum daily. If someone takes longer than 4 days to respond [For example, if the winner hasn't posted a new quote or responded to tell someone whether they guessed correctly or not] a new guess can be posted by anyone.
The person who types the quote always has to add the name of the character who said such quote first so it's easier for everyone to know from which episode it the quote is.
Sheldon: Howard, you know me to be a very smart man. Don't you think that if I were wrong, I'd know it?
Have fun! :D