I've attached some pictures and a pdf file that shows some of the things that I've ended up doing here involving bikes. Here's some more info, feel free to edit and use.
Myself and my wife and 2 kids (with a third due this fall) live and work as volunteers in a village of about 7000 in The Gambia. We work with a Christian organization called Youth with a Mission (see www.ywam.org). My main work is with erosion control and tree planting which are very interconnected and a key issue in this part of the world. I work with villagers to tackle the erosion and we plant trees together. I also try my hand at some farming and gardening, testing out new ideas to see how they work in this degraded soil and hot temperatures. Since 2010, I have also been involved in training some guys in making compressed stabilized earth blocks and have had my hand in building 4 houses out of these blocks.
I have always loved bikes and grew up (in Minnesota) riding and fixing them, but it wasn't until coming to Africa that I really got into them learning the intricacies of repair such as wheel lacing (thanks sheldonbrown.com) and derailleur adjustment, etc. The next logical step was modifying and building them! I learned to weld out of necessity in 2010 (in order to finish up the trusses and ceiling structure of our house) and soon after started being called on to repair or modify bikes in the village.
Bikes here are pretty pricey for African standards and the good ones come used from the US and other western countries. They end their life here and don't die fast as folks continue to fix them until way beyond repair. A common repair is cutting out an old, stripped bottom bracket and welding in a new Chinese one that you can buy for a couple of bucks. Another one is converting a former mountain bike into a single speed which can involve welding rear dropouts on it in order to adjust chain tension. Read more>>