I would say the best thing Ive done while there was cliff-diving in crystal clear waters with some friends.
Basically, I did this because the waters are not shark-infested where I jumped off of. If you like a rush, you'll love it.
When in Somalia/Somaliland make sure to try 'Henna'. Henna is a temporary tattoo-like art. It is common for women to wear it to weddings and very intricate. It wears off in a couple of weeks. Very inexpensive.
Make sure to go to one of the many local markets. They are very lively and full of local people to meet. Note: You will see many Qat vendors. Qat is a mild stimulate chewed by a majority of men in the afternoons and evenings in the Horn of Africa and Southern Arabia.
When in Hargeisa city visit the war memorial in the centre of town. It's an actual Somali Airforce MiG Jet Fighter from 1988-90. During this period the city was bombed extensively by the late Dictator Siyaad Barre. The bombing killed an estimated 50,000 people. Most of the city has been rebuilt, but the people have not forgotten.
Once in Somalia, ask your hotel manager or taxi driver, or locals at a cafe if they know of any local weddings. If your lucky you might be invited to one. It's very lively and colourful, with a lot of food, drinks, and dancing.
Daloh Heritage Reserve.
Golis Range Forest.
This place is huge. It has everything, waterfalls, breath taking subtropical forest, rivers, shallow streams. This region is a habitat for loins, hyenas, and other species unique to that area.
the Golis Range is a breath taking also.