There are a few things worth having a look at here. An interest in Turkey's history will lead you to the Museum of Anatolian Civilisation and there are several other sites of interest. Check out the list below for some ideas.

Museums

• Museum of Anatolian Civilisation
• Museum of Ethnography
• Old Turkish House Museum
• Railway Museum
• Open Air Locomotive Museum
• Republic Museum
• War of Salvation Museum
• Painting and Sculpture Museum
• Presidential Mansion
• Anit Kabir (Ataturk's Mausoleum)

Archaeological Sites

• Hisar (Fortress)
• Column of Julian
• Temple of Augustus
• Roman Baths

Architectural Interest

• Aslanhane Camii - 13th Century Selcuk Mosque
• Haci Bayram Camii - 15th Mosque
• Ankara Opera House ???

Ankara's Hisar

It's very easy to spend a day wandering around Ulus, Samanpazari and, overlooking them both, the labyrinthine alleys of the city's hilltop citadel. On foot or by taxi it's not difficult to reach this area and you'll probably come for the Museum of Anatolian Civilisation anyway. Plan on wandering around for some time.
Once inside the citadel follow the road towards the centre until you pass through an archway, take a right to head up to the Eastern Tower where you'll get your first real impression of how large Ankara has become in the last 70 years. If you can be here for sunset, the call to prayer or preferably both it will make the experience that much more memorable. The area is just starting to realise it's potential as a tourist attraction and tidying up has begun. There's still an untouched feeling to the place that might not last much longer.

Julian's Column

Behind the government buildings at the NE corner of Ulus square is a small park. In the park (Hukumet Meydani) is the Column of Julian. Erected in 362 to commemorate the visit of the then Emperor Julian.

The Temple of Augustus

East of Julian's Column and next to Haci Bayram Mosque are the ruins of a temple standing on a site that has, in it's time, been dedicated to an impressive list of deities. Initially a temple to Cybele, an incarnation of the Mother Goddess associated with Anatolia and an awful lot of other stuff, and Men, a Phrygian god of potency (you get the picture?), it was later dedicated to Emperor Augustus, probably toning down the rites somewhat. Byzantium claimed it for the Eastern church until Muslims built a Mosque on the site, next to the tomb of Haci Bayram. Not the best Roman site but an interesting location.

Roman Baths

The ground plan of the baths is clearly visible and if you know your terminology you'll be able to pick out the apoditerium, frigidarium, tepidarium and caldarium. If not you might not want to take the walk North from Haci Bayram and cross Cankiri Caddesi to find the fenced enclosure that has been erected to protect the site.