Game’s second leg at start of week? (10)
I believe the answer is:
backgammon
'game's' is the definition.
(I know that backgammon is a type of boardgames)
'second leg at start of week?' is the wordplay.
'second' becomes 'back' (to second a motion is to back it).
'leg' becomes 'gam' (informal term for a woman's leg).
'at' is a charade indicator (letters next to each other).
'start of week?' becomes 'mon' (short for Monday).
'back'+'gam'+'mon'='BACKGAMMON'
(Other definitions for backgammon that I've seen before include "Board game played with dice" , "Game with 24 points" , "dicey contest" , "Dice and counter game" , "Dicey business" .)