Armavir  is a city in Central Armenia, past Echmiadzin. It is the capital of the Marz (state) of the same name, though it is probably still called more frequently by its old communist name of Hoktemberyan (in honor of the October Revolution) than by Armavir, the ancient Armenian capital whose ruins are nearby.
Vans (called marshutni) depart from Yerevan to Armavir regularly throughout the day. Taxis in Yerevan are usually happy to take you there for 100 drams (25 cents US) per km. Day tours from Yerevan are offered by some companies by van with other tourists, including guide and sometimes lunch which include the most popular destination of the area, Sardarapat.
Armavir is not a very big town, and is very flat. Walking is an option, or a taxi.
The main site near Armavir is Sardarapat, the site of the monument dedicated to the victory over Turkey, with an attached huge ethnographic museum - the best in Armenia. Aside from that there are the ruins of a few ancient cities, listed below.
There are a few places to eat in Armavir, mostly fast food/cafe type food and Armenian barbecue (khorovats). A few more barbecue places are found on the main highway.
Drinking options are the offered at the same places as food, detailed above.
Armavir has a huge old Soviet hotel which has not been renovated. You can try it for an interesting and potentially cheap option, but Armavir is close to Echmiadzin and Yerevan, where all of the tourists tend to stay. Few even venture off of the highway into this small town.
Vans and taxis are available from Armavir to Yerevan. Along the highway from Armavir to Yerevan you can catch vans and buses heading to Yerevan, or even private cars, but if you are west of Armavir your options are more limited, as there is much less traffic.