Go on gorilla tracking. You'll need to buy a permit which must be booked long time ahead due to limited availability only few tourists are taken near the gorillas a day, in order not to disturb them. With a permit in hand, you are allowed 1 hour on very close hand of a group of the highly endangered mountain gorilla in their natural habitat. Uganda Wildlife Authority handles the sale of permits which cost US$500 each (http://www.uwa.or.ug/). On the 1th of October 2010 the gorilla fee will be raised to US$750. Prices are rising constantly and are expected to continue to rise in the future.
Rafting on the Nile. Uganda is a world class rafting destination and several companies arrange trips down the Nile - from half a day to 2-day trips, from peaceful family trips to very adventurous grade 5 rafting. A rafting adventure with transport from Kampala, including food & drink, will cost about US$125.
Quad biking. Near the Spring of the Nile you can rent quad bikes a 4-wheeled motorbike - also known as All Terrain Bike for a speedy and dusty sightseeing trip with a local guide.
Do horse riding safari around the Nile and local villages.
Go on a Safari.
Go to Sipi, about 1 hour from Mbale. It's a beautiful little town on top of a hill, sporting fantastic views on and hikes to waterfalls. If you don't feel like having a guide, tell them that you'd like to do it yourself and eventually they will leave you alone. Great place to stay over night in Sipi is the Crow's nest with amazing views onto the waterfalls. Crows nest is alright but do not expect hotel quality service, and because of their slow service and bad food bringing our own food is recommended.