Organized mountain bike rides
There are several non-competitive organized rides to choose from every weekend. These are the initiative of Belgium's many bike clubs and other organizations, and they give you a chance to meet up with other mountain bikers, ride a marked route (different choices of 15k and up), enjoy one or two rest stops with snacks and drinks, and at the end you usually have the possibility to wash your bike and take a shower, all at the price of 3-5 euros.
These events are well worth going to since they many times allow you to ride areas that normally aren't accessible to the public. They are non-competitive but you find all levels of riders here, the longer the distance the more advanced the riders.
There are several web sites where you can find information about these rides. None in English. If you dare surf there anyway www.4bikers.be, www.mountainbike.be and www.bikers.be (click on Agenda) are probably the best links.
The bigM group often participates in organized rides. To know where and when, and to possibly hook up with us, you will have to sign up for club membership. Read more here.
For competing/racing you would need an UCI approved licence. The main licensing body in Belgium is http://kbwb.ordina.be/. If you have a license and participate in an event where it is not a requirement, the license can give you a better starting position. For kids (7-14 years), check out the Kid's Trophy.