Remember the long-running TV show America's Funniest Home Videos?  Sure you do.  For me, the first year of watching people get hit in the groin was enough of the subject, but I've found that there's nothing as timeless as a good slap across the face.  Attention Hollywood: If you want me to watch your show, all you need to do is include more slapping.  How I Met Your Mother has followed this formula -- if a one-ingredient recipe can indeed be called a "formula" -- perfectly by not only including slapping, but the anticipation of slapping.  If you're not familiar with the series, I'll keep this post short and let the slaps speak for themselves...

Update: After a little research, I have found the Official Slap Bet rules.  Credit to TV Squad:

1. A slap bet is created when two parties involved in a disagreement, argument, or difference of opinion mutually agree that whichever party is proven right (or winning party) gets to slap whichever party is proven wrong (or losing party) across the face as hard as they possibly can.
2. In all Slap Bets, a Slap Bet Commissioner must be appointed. In the event of a discrepancy, the Slap Bet Commissioner makes the final ruling. The Slap Bet Commissioner must be someone fair and unbiased, someone kind hearted but not afraid to rule with an iron wrist.
3. When issuing a slap, the slapper must avoid lips and noses at all costs. The goal is for the palm of the slapper's hand to connect with the meaty part of the slappee's cheek thus providing utmost enjoyment and pain. If you're seeing handprint on cheek, you're doing something right. In the event of a bloody nose, the Slap Bet Commissioner shall award the slappee three slaps to be used in succession. Suggestion: The Dead Man's slap (rule 8.)
4. When issuing a slap, the slapper must not wear any rings, gloves, or other finger/hand ornaments to protect the safety of the slappee.
5. When issuing a slap, the slapper must keep one foot on the ground at all times to protect the safety of the slappee.
6. In the event of Premature Slapulation, (when the slapper slaps the slappee as hard as he or she possibly can and then afterwards, finds out that the slap was not warranted), the slappee gets to slap the slapper at least three times.
7. The Blind Man Slap: If the Slap Bet Commissioner deems the slappee particularly deserving, the Slap Bet Commissioner can issue The Blind Man Slap in which the slappee must close their eyes while being slapped.
8. The Dead Man Slap: Backhanded slaps are permitted only if used in succession. For example, if the Slap Bet Commissioner awards the slapper multiple slaps, the slapper can use a backhand if and only if it's preceded by a forehand. This is commonly referred to as The Dead Man Slap and is the only existing slap that allows the slapper to connect with both sides of the slappee's face thereby earning maximum slappa
9. When the slappee gets slapped, he/she must accept the fact that they've just got slapped. Any retaliation against the slapper, by the slappee, will result in no less than ten slaps (with a set number to be delivered by the Slap Bet Commissioner.)
10. The most important rule: Enjoy! Few things in this world match the sheer joy one receives from slapping a friend right across the face. Especially after being proven right. So slap away!