I was at a conference in Birmingham once.
I popped out for a walk shop and I was grabbed by a bloke outside the town hall.
He asked me to be a witness at his friends wedding. Theirs had not turned up.
In fact none of their guests or family had turned up 
They were a couple with two children and they were all dressed up to the nines in a um er interesting way.
The bloke who grabbed me had on one of those sky blue polyester suits and a frilly shirt and a really old fashioned hearing aid (like the one Morrisey used to wear).
When they were getting married the woman started to cry (happy tears) and her DD got all worried and remember saying 'you know mum is crying because she is happy dont you?'
I gave the DD a fiver or a tenner (dont remember) and said 'buy mummy and daddy a wedding present' (I didnt know the ettiquette for that sort of thing but I felt the need to contribute something 
).
I did it quitely but the DD was so shocked she sort of waved it about and they all looked at it as if I had given them £10,000!
Mum started crying again.
It was all weird and touching and lovely and strange at the same time.
A few months later I got a really blurry photo in the post and lots of confetti 
I had forgotten all about it till I saw this thread!