From my other thread, but this needs it's own attention:

I need to be 'off sick' next Thursday and Friday as I have booked flights away but don't have any holiday. What's the best and most convincing method of being 'sick'. Should I tell them I'm going to be in hospital or do it on the day? I have a VERY Important meeting that day so it has to be good.

What are your best excuses? - one's you've really used please.