From serious campaigners with a clear message to wombles, clowns, golfers and extremists, Scotland is expecting a variety of visitors this week.
Who is involved and what are their objectives? BBC Scotland's news website examines the main groups expected to make their presence known.
MAKE POVERTY HISTORY (MPH)
An umbrella group comprising hundreds of thousands of concerned members of the public, charities, trades unions, churches and celebrities.
It is arguing for improved trade, aid and debt relief for the poor parts of the world.
MPH is behind the anti-poverty march in Edinburgh on Saturday, 2 July and has had huge success with fast-selling white wristbands and television adverts.
STOP THE WAR COALITION
This group organised the largest-ever protest on British soil on 15 February and argues that preventing wars is vital in tackling poverty.
An organised demo is to be held by members of the group in Edinburgh on Sunday.
Its leaders have been at loggerheads with police and the local council over plans to march outside Gleneagles Hotel at the start of the summit on Wednesday, 6 July - probably the week's second-biggest protest.
As well as calling for improvements in Third World development, the campaigners argue global capitalism is inherently unjust.
The group has helped co-ordinate blockades against Faslane naval base, home to Scotland's nuclear warheads and the Dungavel asylum detention centre in Lanarkshire.
The Dissent Network is setting up a base in Glasgow and claims to provide a networking tool to co-ordinate radical resistance to the summit.
A key plank of the group's Gleneagles protest will be attempts to blockade access points to and from the venue, causing maximum disruption.
The main blockades will take place on the morning of Wednesday, 6 July - the first day of business - to prevent the delegates and their support staff reaching their destination.
The "White Overall Movement for Building Liberation through Effective Struggles" is said to have been responsible for much of the May Day chaos that ensued in London back in 2001.
The group has already issued an e-mail appeal to anti -capitalists to bring drums and musical instruments on Monday, 4 July to create a "carnival atmosphere" on city streets.
However clashes are feared if the group tries to block off or enter the offices of Edinburgh's big financial institutions.
Leaflets have already been handed out to staff at Standard Life and the Royal Bank of Scotland by the group asking them not to turn up for work.
CLANDESTINE INSURGENT REBEL CLOWN ARMY
Also known as CIRCA, members of the group are easily spotted in their respective clown outfits and colourful face paint.
It has been involved in a number of protests in the past and members plan to use props such as tickling sticks and custard pies to harass police officers.
The group has said it will launch "Operation HAHAHAA (Helping Authorities House Arrest Half-witted Authoritarian Androids)" during which it plans to "help the security forces keep the G8 under indefinite house arrest."
PEOPLE'S GOLFING ASSOCIATION (PGA)
This group of anarchist golfers have pledged to hold their own tournament on the manicured lawns of Gleneagles during the summit.
Pictures have already been circulated on the internet of balaclava-clad members standing on the 18th green at Gleneagles back in December.
They also hope to organise a "crazy G8 golf tournament" with holes such as a large sand-trap in the shape of Iraq and a pond in the shape of Guantanamo Bay promised.
The bloc originated in Germany in the 1980s and the catch-all term is understood to have been used by police to describe collective action by anarchists.
Black has traditionally been a colour associated with anarchism and is worn by many anarchists because it helps to ensure anonymity.
There is no one issue which prompts Black Bloc action, the main aim being to gather to oppose "repressive" action by the establishment, wherever that may be.
Those who have engaged in Black Bloc action, which has spilled over into violence, point the finger at the police, claiming that it is their response to collective action which provides the trigger for violence.
Notable Black Bloc activity includes the anti-World Trade Organisation protest in Seattle in 1999 when anarchists clashed with police.