The Isle of Man is the home of motorcycle road racing in the world, with two separate events held in a year - the TT (early June) and the Grand Prix (end of August). This route marks the 37.73 mile circuit, which are all regular roads (except for a small turning before the starting straight in Douglas). it begins in Douglas, going clockwise around the route.
The scenery varies from small, pretty villages and normal towns (strict 30mph limits with police presence) and a wide variety of roads cutting through the countryside, woods and mountains - the majority of which have NO speed limits. The view up the mountain is spectacular, if you have chance to look!
The fastest lap (2009) is currently 17min 12 sec, or an average speed of 131.578mph. To make this possible, nearly all of the route is race track smooth, with a couple of bumpy sections on the approach to Ramsey. However, these roads are used like any other roads, so expect a mixture of traffic along the route.
To get to the island, you're best taking your own bike from Ireland or England, the Steam Packet Company are the only ferry operators. There is an airport, but if you can't take your bike what's the point?! There are plenty of good B&Bs and hotels, or there's camping sites as well. It's not part of the UK, but rather a British Crown Dependency - if you are British or can freely travel to the UK, you'll have no problems visiting the Isle of Man.
Most people visit during the race weeks, when there's a lot going on and you can find many good vantage points for viewing the races. It's good at other times when it's a lot quieter and you can enjoy more freedom on the road. Go with a group and you'll have a laugh.