[After Ryan and Esposito catch a break in their case]
Castle: I've got a bad feeling about this.
Beckett: Are we really rooting against solving a murder?
Castle: Well, I don't want to shave my head! Do you?
Beckett: Why would I shave my head?
Castle: You're in on the bet, aren't you?
Beckett: Yeah, but I didn't realize-
Castle: [imitates electric razor]
Castle: I've got a bad feeling about this.
Beckett: Are we really rooting against solving a murder?
Castle: Well, I don't want to shave my head! Do you?
Beckett: Why would I shave my head?
Castle: You're in on the bet, aren't you?
Beckett: Yeah, but I didn't realize-
Castle: [imitates electric razor]
[After Ryan and Esposito catch a break in their case]
Castle : I've got a bad feeling about this.
Beckett : Are we really rooting against solving a murder?
Castle : Well, I don't want to shave my head! Do you?
Beckett : Why would I shave my head?
Castle : You're in on the bet, aren't you?
Beckett : Yeah, but I didn't realize-
Castle : [imitates electric razor]
http://www.tv-quotes.com/shows/castle/quote_23832.html