A Tourist visa is given to those visiting India for tourism or other non-business related purposes. You should apply for a Tourist Visa only.
e-Tourist Visa Facility is available for some Nationalities. With the eVisa your landing airport is from any of the 16 designated Airports where the e-TV facilities are available such as Ahmedabad, Amritsar, Bengaluru, Chennai, Delhi, Gaya, Goa, Hyderabad, Jaipur, Kochi, Kolkata, Lucknow, Mumbai, Tiruchirapalli, Trivandrum and Varanasi. You can depart from any of the Airports that have an Immigration Check Point without any intimation to them.
The GopherConIndia organizers are happy to provide an invitation letter if you need one; we do suggest, however, that you check with your local embassy or consulate, as requirements differ from country to country. Do apply for your Indian Tourist Visa definitely by mid Nov. 2016.