The cartoon bomb Stick sheets of loo paper up the guy's arse. Then light it - he has that long before to down the drink before his arse gets burned. Namecheck At the start of the night either go with the stag's name or his wife's / ex girlfriend and make sure his drinks all start with the letters of the name in order. So someone marrying SHARON gets a pint of Smiths to start, followed by a ... Then at least when the poor sod turns up a bit worse for where the next day, you can blame it on the bride! A romantic evening for 2! When he's wrecked, you can book him in to the dodgiest hotel you can find. Leave him there with a pair of old male pants, a note from someone saying "thanks for a great night - enjoy your marriage... you fraud, love Jonny" or words to that effect. Ask the receptionist to tell him that his boyfriend checked out a couple of hours ago etc. When he gets back to the group subtly ask "what happened to you last night? Did that bloke's sister actually turn up" - mention that you thought he seemed to be quite camp and that if it wasn't for him getting his sister to come to the hotel for you, you'd swear that he was interested himself! Extra points: used condom in room 'evidence', put a couple of drops of tobasco on his ass to make it sting.