Bruges (Brugge) is a town in Belgium.
Take the bus for 'Loppem' from the main station. Get off at the stop just before Loppem village. There is a motorway exit to stand at 200m from here.
Method 1: Walk away from the station of Brugge, direction A17 is your best shot. Heading St-Michiels, at the Koning Albert laan, there are some Gas stations, and this road leads to all major motorways. It's still easy to stop here for cars to pick someone up.
To get to there from the Brugge train station you can take bus number 7 heading for cinema center Kinepolis and then just follow the people going to the cinema:), as it is located very close to the motorways.
Addition on 8 Feb 2011: Reconstruction of the 'Expresweg' of E403/N351 around Bruges, makes it now NOT the best place to hitchhike out of Bruges. Before it were good, fast and safe spots. Now I would prefer Method 2.
Method 2: Go to the beginning of the 'Baron Ruzettelaan' (10/15 min walk from train station and city centre). There are 2 gas stations, people drive slow and there is enough place to pull over. Even by night it's a great spot. Once there, you hold up a sign that says '4km', ask if they go to 'Oostkamp' (Most people are), and if they could drop you off at the entrance of the motorway there (E40).
From that entrance in Oostkamp, you can go in any direction and country. Make a sign that says: 'Gent', 'Torhout' or 'Jabbeke'.
Waiting time for the 2 spots are very little.
When getting out of the main entrance of the train station, walk straight and follow the main road to the right. Walk straight for about 1,5 km. You'll pass some bus parkings, some small channels and a huge bridge. Just behind this bridge, at the traffic light, walk to the right again. There you'll find three petrol stations. You can just hitch next to the road at the first or second station, passing traffic can easily stop here. Most rides go to Oostkamp, ask your driver to drop you out close to the on-ramp of the highway. There, you can continue hitchhiking east- or westwards.