From: http://www.bbc.co.uk/worldservice/learningenglish/language/2014/05/140527_todays_phrase_whats_up.shtml
A one-way road sign in London
Today's Phrase
When you want someone to tell you about a problem, you can ask them: what's up?
Examples:
What's up? I came to your house to party and everybody is sitting around looking sad.
What's up with Lauren? She's been acting in a very strange way.
Take note
In American English, you'll often hear the phrase what's up?Here it's being used as an informal greeting between friends.
Example:
What's up, Frank? I haven't seen you for ages.
Interesting fact
According to the website DriverAbroad.com, around 66% of the world's population live in countries where drivers use the right side of the road. There are 76 countries, territories and dependencies in which they drive on the left. Among these are India, Japan and the United Kingdom.