This below question is from the Play of the Day- an email sent to you daily with an NF rule question. Most are good basic questions which are good refreshers daily. I included the sign up info below if you are interested.
Fourth and 8 from the 50. K1's punt is high and short. R1, standing at his (a) 46 or (b) 49, gives an invalid fair catch signal, after which he muffs the punt. The muffed punt strikes the ground at R's 45, then bounces back to K's 49, where it is recovered by K2, who advances to R's 40, where he fumbles. R2 recovers K2's fumble at R's 39 and returns the fumble for a touchdown.
POTD
(Play of the Day)
Pass the play of the day along to your fellow officials. For signup instructions goto:
http://www.nafoa.net/PlayOfTheDay1.htm