All-round fantastic trip

The program focus is very much on teaching. However, it is very much up to you to make sure you have a positive impact at the schools at which you are teaching. In your (relatively short) time there, make sure to quickly identify what problems your pupils are having in their understanding of the English language, and then identify which one's you can make a real difference on in your short time there.
Outside of school, there are plenty of things to do, as well. The school day is relatively short, so make sure you make the most of your free time. You'll be living with a working family so you'll definitely get a 'real' experience, but make sure to explore the local area to get a good sense of what its like to actually live in Nepal (rather than just holiday there).
I did lots of longs walks, and took trips around the country on the weekend. I went to Pokhara (Nepal's second city), went paragliding, bungee jumping, and hill walking. I also went on safari in Chitwan National Park, seeing elephants, rhino and monkeys. At one point, when I got a bit longer time off (during a school holiday), my group and I even went to Tibet! The Tibet trip is fantastic and really worth doing.
The support from the Oyster contacts in Kathmandu is fantastic. Basant's main business is as a travel agent, so he can actually help you out a lot in terms of organising things to do in your free time.