My favourite, which I think is original, isn't on the list:
"When the Irresistible Force meets the Immovable Object it's time for a tea break."
Then there's the well known Universal Law of Junk:
"The only piece of junk you will ever need is the one you threw out last week."
I don't know where this one came from:
"There are two kinds of people: those who divide people into two kinds and those who don't."