In How I Met Your Mother Barney lost the Slap Bet some time ago. Being a somewhat inconsistent viewer, I can't recall the episodes that fulfilled the bet, and in my mind, at least 1 is still due. What is the count outstanding on this?
In "Slap Bet" (Season 2 Episode 9) Marshall was granted 5 slaps to be delivered any time in the future without warning.
5 + 3 = 8
out of which
slaps have been executed.
The 1st slap was executed in "Slap Bet" (Season 2 Episode 9)
The 2nd slap was executed in "Stuff" (Season 2 Episode 16)
The 3rd slap was executed in "Slapsgiving" (Season 3 Episode 9)
The 4th slap was executed in "Slapsgiving 2: Revenge of the Slap" (Season 5 Episode 9)
The 5th and 6th slap were executed in "Disaster Averted" (Season 7 Episode 9)
Hence, there are
2 slaps remaining.
On a related note, the 7th slap has a countdown at Slapbet Countdown! :D
According to the How I Met Your Mother wiki, the original five slaps have all been used. However, Barney offered Marshall another three as payment on a separate bet, one of which has been used. Two remain as of this date.